It is a remarkable night and it is difficult to argue Bradford do not deserve it after a gutsy display. Arsenal's players choked in the shoot-out. Pressure on Wenger will now be immense and it was only Vermaelen's late header in normal time, which cancelled out Garry Thompson's effort which saved the Premier League club. The scenes of celebration will go on for a long time at Valley Parade. Is this the greatest night in Bradford's history? What now for Wenger and Arsenal?
George Matthews says: "I cannot believe Arsenal have just lost to Bradford. Arsene Wenger has had his time, it is about time he quit. We need to get a fresh new manager in charge of the Gunners, this is just embarrassing."
A thrilling night ends in Bradford's ninth successive penalty win. They win the shoot-out 3-2 and reach the League Cup semi-finals for the first time in their history. Stay with us for all the post-match reaction.
Vermaelen hits the post! Bradford win (3-2)!!!
R.Jones' penalty is poor and Szczesny saves. Arsenal live on (3-2)
Oxlade-Chamberlain had to score or it was all over. He does not fail (3-2). Next penalty can win it for Bradford.
Connell keeps his cool and scores (3-1)
Wilshere makes no mistake with a low spot-kick (2-1)
Darby sees Szczesny save his poor spot-kick when diving low to his left (2-0)
Chamakh hits the post and also misses (2-0)
G.Jones hits his penalty to Szczesny's right and beats the goalkeeper (2-0)
Cazorla has his spot-kick saved by Duke (1-0)
Doyle scores despite Szczesny getting a hand to the ball (1-0)
George Matthews says: "I can't believe it has gone to penalties. If Arsenal lose, I think we all want Wenger out!"
Remember, Bradford have won their last eight penalty shoot-outs. They defeated Wigan on spot-kicks in the last round.
120 + 1
EXTRA-TIME - FULL-TIME: BRADFORD 1 ARSENAL 1 - PENALTIES ARE REQURIED
ADDED TIME: There will be a minimum of one minute added time before the match goes to penalties.
Mertesacker handles the ball just inside the Bradford half to give away a free-kick. That might be enough to see Bradford to penalties.
Turgott is refusing to give Vermaelen any rest at the back and is chasing every ball even if it is a lost cause.
What a waste from Rosicky as he hits a cross out of play when putting too much power on the ball. Arsenal's crossing tonight has been poor. The one time they got it right, Vermaelen scored.
Turgott tries to hold the ball by one of Arsenal's corner flags but runs it out of play. Ironic cheers from the travelling Arsenal fans.
Oxlade-Chamberlain has a rant at Chamakh after the striker sells his team-mate short with a pass inside the penalty area. Oxlade-Chamberlain is right to be annoyed it was a poor ball.
Bradford have the ball in the Arsenal half on a rare occasion but Connell is offside.
Terrible from Oxlade-Chamberlain. He is wide on the right and under no pressure but slices his cross out for a goal-kick. He hangs rightly his head in embarrassment.
Bradford look out on their feet but they are just around eight minutes away from a penalty shoot-out, when they will be confident.
This time Cazorla's shooting is not so good as the Spaniard hits an effort well wide from 20 yards with his right foot.
Gervinho has not had a good game. He missed that great chance in normal time and now has strayed offside.
After collecting a pass from Sagna, Cazorla rattles the Bradford crossbar with a dipping, swerving left-foot effort from 25 yards. Duke was well beaten. It was a super strike from Cazorla.
Bradford hit a long ball for Turgott to chase. Vermaelen lets the ball bounce but Szczesny is out of his area to volley clear.
Just wide from Chamakh. He attacked yet another Cazorla corner and nods only a foot or so past the far post.
The game picks up where it left off. Bradford are on the edge of their box and Arsenal are attempting to find their way through.
Bradford get the second half of extra time under way.
EXTRA-TIME - HALF-TIME: BRADFORD 1 ARSENAL 1
At the risk of being on repeat, another corner for Arsenal. Cazorla takes and McArdle's glancing header is enough to clear.
After a few ricochet, Turgott has the ball on the edge of the Arsenal box. But he tries to beat Vermaelen when he had the chance to pass wide to Connell. Bradford want handball against Vermaelen but there is nothing in it.
Bradford are in no rush when the ball is in the hands of Duke. They want penalties. Do not forget they have won their last eight shoot-outs. But they have a long time to hang on.
Yet another corner for Arsenal. Chamakh meets Cazorla's set-piece but can only head up in the air and Duke comes out to claim.
Bradford are now playing without any strikers. Even Connell is getting pulled back. They have no out-ball when they do get possession.
Cazorla's first corner is cleared but Sagna follows up with a header which has to be nodded clear by G.Jones at the back post.
Arsenal win another corner through Gibbs.
It has been noticeable how many Arsenal crosses have gone to waste this evening. Without Giroud they have no aerial threat in their attack. Only when Vermaelen, at his goal, and Mertesacker are forward do they pose a danger.
Superb from Wilshere as he breaks into the box after playing a one-two with Chamakh. But when he has the chance to shoot on his right he tries to get back on to his favoured left. He ultimately only wins a corner, which Bradford can defend.
Connell is the lone man up front for Bradford and he has the chance to run the ball but is soon robbed of possession when up against three Arsenal defenders.
Bradford are again positioned back on the edge of their box with their defence and midfield in two banks of four. They are hoping to soak up Arsenal attacks.
Oxlade-Chamberlain is screaming for handball in the Bradford box after his shot is blocked by McHugh. Replays suggest it did hit the arm of the Bradford defender but the officials are not interested.
At the break in play, Bradford replace Atkinson with Turgott.
Vermaelen is booked for another foul. It has been persistent fouls from the Arsenal captain.
Bradford will do well to get a foot back in this game after being dominated for so long.
Arsenal get the first period of extra time under way.
90 + 4
FULL-TIME: BRADFORD 1 ARSENAL 1 - EXTRA TIME IS REQUIRED
90 + 4
Duke dives to his right to save Cazorla's free-kick and then is back on his feet quickly to save a follow-up effort.
90 + 3
Bradford have hardly been out of their half in the last 20 minutes and have to fear for them in whatever remains of this game. Doyle gives away a free-kick and is booked around 30 yards from goal.
90 + 2
Really poor from Gibbs as he wanders offside on the left when Arsenal were stationed on the edge of the Bradford box.
90 + 1
Chamakh has made next to no impact since coming on and, when attempting to get behind the Bradford defence, he goes offside.
ADDED TIME: There will be a minimum of four added minutes before the final whistle and potential extra time.
Arsenal now fancy they can win this in normal time. Rosicky hits a 20-yard effort just wide with his right foot.
It is heartbreaking for Bradford as they came so close to winning in normal time but have been pegged back at 1-1 . They cleared Cazorla's initial corner but the Spaniard's follow-up cross found Vermaelen completely unmarked at the back post and he made no mistake with a close-range header.
GOAL VERMAELEN (1-1)!!!
Corner to Arsenal as Doyle, who has been superb, deflects a Cazorla shot behind.
Free-kick to Arsenal and a chance to load the ball into the box. But Wilshere's set-piece is terribly under-hit. Mertesacker can flick it on but it is simple save for Duke.
There is an eerie atmosphere at Valley Parade. The home fans cannot quite believe how close their side are to reaching the League Cup semi-finals for the first time in their history.
Rosicky plays in Gervinho, who squares the ball back to the penalty spot perfectly for Oxlade-Chamberlain. But the substitute puts it over the crossbar.
Sagna gets to the right byline and digs out a cross but it is blocked by McHugh and then cleared by Meredith.
Wilshere is trying to take the game by the scruff of the neck. He looks frustrated and is demanding the ball at every opportunity.
Wilshere bursts out of midfield with a change of paste and tests Duke from 25 yards with a low left-foot shot. Duke palms it wide and one of his defenders follows up to clear.
We are in to the final 10 minutes and Bradford nerves will be shredding.
Bradford may be surrendering a lot of possession and territory but they are not exactly on the ropes. Arsenal look a little short on ideas when they get within sight of goal.
G.Jones' delivery is poor and it does not clear the first defender. Arsenal go back on the attack.
Free-kick to Bradford in the Arsenal half as Wilshere fouls R.Jones. This is a chance for G.Jones to cross the ball into the box.
Meredith does not fall for a Oxlade-Chamberlain trick and tackles the England international before running forward with the ball. But Bradford cannot keep the ball and it comes back at them.
Arsenal have not had a problem in attacking Bradford in wide areas. But Bradford's central area have been too well organised to offer anything in the middle of the pitch.
The excellent Wells is going off and boyhood Arsenal fan Connell is coming on. That is a change of a striker for a striker. Bradford are still looking to attack when they can.
Bradford are camped in their own half. They have no out ball when they do get possession. Arsenal, though, are not peppering Duke's goal.
Goalscorer Thompson is off to be replaced by R. Jones.
Arsenal win a corner but Hanson heads clear. Bradford are beginning to be pinned in their own penalty area. Gervinho is back through the middle with Chamakh, with Oxlade-Chamberlain wide on the right.
Arsenal are beginning to turn the screw and Oxalde Chamberlain immediately brings the first save of the night from Duke.
Ramsey, bloodied nose and all, is replaced by Rosicky and Podolski is off for Oxlade-Chamberlain to come on.
Wells is correctly booked for a late challenge on Wilshere.
Arsenal are still struggling to get a shot on target. They have yet to test Duke.
Chamakh holds his hands out as if to say, 'come on' to his team-mates. But he has no-one but himself to blame after giving the ball away.
Doyle has had a very good game. He holds off two Arsenal midfielders before playing a pass in field to keep the ball for Bradford.
Ramsey is back on but is still perhaps a little rattled from his whack to the face as he gives the ball away when attempting a simple short pass to Cazorla.
Play is back under way. But Hanson then wins another free-kick from Vermaelen. The Arsenal captain has been naive at times in challenges this evening.
Ramsey is back on his feet and is okay to walk off the field to receive more treatment but he appears to have a bleeding nose.
Chamakh is playing through the centre in attack, with Gervinho having pushed out to the right. We have a break in play after Ramsey takes an accidental boot in the face from Hanson.
Arsenal make their first change of the night. Coquelin's evening is over and Chamakh comes on in his place.
But despite Arsenal pushing their hosts back, it is still the old criticism of them being guilty of overdoing things in their opponents' penalty area.
Coquelin ghosts to the byline on the right but his cross dissects all of his team-mates and Bradford survive. Arsenal are beginning to push Bradford back.
Really poor from Podolski. Arsenal are looking to move forward at speed and Ramsey and Wilshere are overloading on the right but Podolski gives away possession when attempting to spread it from left to right.
Gervinho looks like he has go in behind the Bradford defence but the ball does not quite fall for him. Doyle then does superbly to see the ball out of play when under pressure from Ramsey.
From Coquelin's header, Arsenal move up field and speed. But Ramsey slices an effort wide from inside the penalty area. Arsenal have still to have a shot on target this evening.
But now Bradford do win a free-kick on the right and not too far from the corner of the Arsenal box. set-piece specialist Jones delivers the ball but it is headed away by Coquelin.
Bradford should have another corner but the officials do not spot the ball comes off Coquelin when challenging McHugh.
Bradford waste the free-kick when it is over hit. But they return the ball into the Arsenal territory. Wells wins a corner on the right. Mertesacker wins the header to nod clear.
Foolish challenge from Vermaelen wide on the right in the back of Hanson. The striker was always looking for the foul and it is a chance for Bradford to launch the ball into the box.
Bradford have already dropped deeper than the high line they were playing in the first half. That could invite pressure.
The Bradford fans are still in full voice but there is a little sense of nerves around the stadium. They know Arsenal are going to have a period of attacking at some point.
The counter-attack leads to a cross towards Hanson at the far post but the tall striker does not quite have long enough legs to bring the ball under control.
A dangerous Gibbs cross has to be headed clear at the near post by McArdle and Bradford break up field.
There were no substitutions at half-time. Both Parkinson and Wenger have stuck with their starting line-ups.
WE'RE BACK: Bradford get the second half going.
Conor Wells says: "Arsenal have to improve or it's going to be a long night for them. Congrats to Bradford but arsenal need something fast."
Danny Spring says: "Arsenal are making plenty of chances, because of that I'm predicting a 3-1 win. If Arsenal make it 1-1, Bradford will collapse."
As well as they have played, suspect Bradford might regret that late missed chance from Wells which trickled just past the post. Arsenal are bound to crank up the pressure.
Bilal Hussain says: "Hope Wenger changes something, maybe Ramsey for Chamberlain. We need some pace in this squad!!"
Thompson's 16th minute goal means Bradford are just 45 minutes away from the first League Cup semi-finals in the club's history. Arsenal have been guilty of missing chances. But Hanson and Wells have proved difficult opponents for the Arsenal defence and look a constant threat.
45 + 1
HALF-TIME: BRADFORD 1 ARSENAL 0
45 + 1
Doyle is fortunate not to give away a foul when clobbering Wilshere in midfield with a late challenge.
ADDED TIME: There will be a minimum of one minute added time before half-time.
Agonising for Wells. Hanson wins another flick on and Wells beats Vermaelen to the ball. He pokes his foot on the ball and prods it past Szczesny from inside the box. However, the ball trickles just wide of the far post of the unguarded goal.
The Arsenal bench does not look overly worried as we approach the break. They will know there is still a long way to go. Bradford, though, will be delighted with how the first half has unfolded.
Arsenal have been guilty of wasting chances. Vermaelen had a good header earlier in the piece and they cannot afford to keep making mistakes.
What a chance for Gervinho. Arsenal work the ball wide to the left and Gibbs has space to cross. His low ball finds Gervinho inside the six-yard box but the forward somehow fails to connect when attempting a side-foot. He was perhaps distracted by Dukes diving just in front of him but there is still not really an excuse.
With five minutes plus added time to go until the break, Bradford will know it is vital they do not concede.
Cazorla has Dukes a little worried with a swerving effort from a central position on the edge of the 18-yard area but it curls wide.
Again, play immediately moves to the other end of the field and Bradford win another free-kick on the right and in a similar area to where they scored. But Hanson, at the back post, strays offside from the set-piece.
Coquelin hits the post. After a lovely double step-over and the benefit of a bit of a ricochet off Doyle, the midfield hits a low, skidding effort which beats Duke and bounces away of the base of his left post.
Another long throw goes in to the Arsenal box and Hanson again wins the flick on. The ball goes over the head of Mertesacker and bounces in front of Arsenal's back post. Szczesny can claim unchallenged as no Bradford attacker anticipated the dropping ball.
Ramsey is not impressed with a decision to award a goal-kick when he wanted a corner in a challenge with Meredith. But replays show referee Mike Dean got the correct decision.
A long pass down the inside right channel towards Well's pace remains a recurring theme for Bradford. It is clearly a tactic they have worked on in preparation for the game.
Cazorla spreads the play to the left and Gibbs latches on to a knock down. The left-back smacks a 25-yard volley just over the crossbar but had handled the ball in the build-up to give away a free-kick.
It cannot be argued Bradford do not deserve their lead. Wells and Hanson are proving a real handful and have been a threat. They are full of confidence given Bradford's recent good form.
Bradford head clear Cazorla's corner from the left and Wilshere hits his 20-yard follow up high over the crossbar.
The game is continuing in an end-to-end fashion. Wilshere wins Arsenal a corner.
Mertesacker heads the corner away but Bradford keep the pressure on and return the ball into the Arsenal box. Goalscorer Thompson does not realise he has time and cannot wait for the ball to come down when hitting a weak overhead kick at goal.
Bradford charge up field and Wells wins a corner on the left from Vermaelen.
Cazorla is tripped 20 yards from the Bradford goal at the conclusion of the counter-attack and it is a free-kick to Arsenal. Danger for Bradford. Podolski takes the free-kick and hits it into the Bradford wall. Replays show the ball hit a raised arm in the Bradford wall.
The throw goes long in to the Arsenal box where it is cleared to 20 yards from goal. Meredith follows up with a first-time volley but it is charged down and Arsenal break up field.
Arsenal give the ball away in the attacking third and Wells can again carry possession down field before winning a throw-in in the Arsenal half.
Arsenal have struggled to get Wilshere and Coquelin into the game so far. Cazorla is the only midfielder really having an impact for the away side as Bradford are bypassing the centre of the pitch.
Another Jones set-piece causes panic in the Arsenal box. Gibbs has to hack the corner away at the near post after Arsenal failed to deliver with the first ball.
Another corner to Bradford as Hanson again out-jumps Mertesacker. Bradford are winning everything in the air.
Wells again gets free down the right. But, with Hanson and Atkinson waiting in the box, his cross is poor and blocked by the first Arsenal defender.
Bradford are continuing to look a threat on the counter-attack when breaking at speed against Mertesacker and Vermaelen.
Gibbs makes a nice angle when getting to the byline on the left but the move breaks down. Arsenal have not been able to find the right final ball yet.
Wells is proving a real handful for Vermaelen. Bradford are currently targeting long passes down the inside right channel in an attempt to use Wells' pace.
Arsenal move straight back up field and are looking for an immediate response. There is too much on Cazorla's corner and it clears all his Arsenal team-mates in the box.
From Sagna's wasted cross, Bradford moved up field and won a free-kick on the right when Wells is blocked off by Vermaelen. Arsenal were marking zonally and got exposed from Jones' crossed free-kick. Atkinson flicked on the free-kick and Thompson extended a long leg at the back post to poke the ball into the back of the net. Wild scenes of celebration at Valley Parade.
GOAL THOMPSON (1-0)!!!
Sagna is being given far too much room by the Bradford defence. Meredith is not getting tight enough. Fortunately for Bradford. Sagna's crosses have so far been inaccurate.
Hanson and Wells have done okay in the opening 14 minutes. But they need to be careful their enthusiasm does not lead them to commit too many fouls against Vermaelen and Mertesacker. It is simply giving the centre-backs an easy escape route.
Bradford play a high line in an attempt to catch Gervinho offside and are successful. They hit the free-kick long down field and Hanson gives away a foul.
Arsenal are beginning to show some nice touches in front of goal and the pressure is building on Bradford. But the home side still look like they are capable of worrying Vermaelen and Mertesacker.
Lovely stuff from Wilshere who shapes to shoot on the edge of the Bradford box but instead scoops a crossed pass to Podolski. The German has to react quickly and heads over the bar.
Mertesacker's wobbly start continues as he almost allows Hanson to latch on to a long, bouncing ball. Szczesny is off his line quickly to dive and grab the ball.
Arsenal are beginning to build some pressure and a Gervinho cross-shot is deflected for a corner. From Cazorla's set-piece, Vermaelen wastes a great chance when heading, unmarked, over the crossbar at the back post.
Bradford clear Cazorla's initial corner and then, from Sagna's follow-up cross, Gervinho is correctly booked for deliberate handball when punching the ball in an aerial challenge with McHugh.
From the free-kick, Arsenal move up field and Sagna cross from the right. Darby heads the cross behind at the back post for a corner.
Mertesacker and Vermaelen have had a bit of a shaky start. Hanson and Wells are not afraid to put themselves about. Vermaelen lets a ball bounce inside the penalty area and is grateful to be fouled by Wells.
Bradford are looking for tall striker Hanson with long balls and a cross from the right finds the forward. But Hanson is well offside when inside the penalty area..
Coquelin, though, leads a burst into the penalty area before playing the ball wide to Ramsey. But Ramsey's return pass has too much power and Coquelin is unable to control it.
Bradford are pushing Arsenal with a high line in an attempt to put Wenger's men off their passing game.
Bradford take the free-kick short and work their way to the byline of a very frosty pitch. Vermaelen then has to scoop the ball clear at the near post.
Early free-kick for Bradford in the Arsenal box after Gibbs trips Thompson.
KICK-OFF: Arsenal get the game going.
The teams emerge from the Valley Parade tunnel to a great din of cheers from the home fans in West Yorkshire before going through the pre-match handshakes.
Thanks for all your email and tweets and sorry I have not been able to publish them all before kick-off. Keep your views coming throughout the game at firstname.lastname@example.org or via Twitter @SkySportsPeteF.
With less than 10 minutes to kick-off, here is a round-up of the team news. Arsenal boss Wenger breaks his long-held rule by fielding a strong side. With the Gunners seeking to end a seven-year barren chase for silverware, Wenger makes just three changes from the side who beat West Bromwich Albion in the Premier League - Francis Coquelin, Aaron Ramsey and Lukas Podolski coming in for Alex Oxlade-Chamberlain, Mikel Arteta and the injured Olivier Giroud. Wenger has previously only fielded full-strength sides in a League Cup final, and his team line-up was greeted by groans by fans of Bradford - who were unchanged from their win at Torquay - at Valley Parade.
Bradford are unsurprisingly the hefty outsiders tonight at 9/1 while Arsenal are 2/7 to progress in normal time, with extra time 9/2. The Bantams are 9/2 in our 'to qualify' market while Lukas Podolski heads the first goalscorer betting at 7/2.
Wenger himself is aware of the Valley Parade atmosphere. He said earlier in the week: "It was a difficult place to go to when we played there in the Premier League. It is a passionate place with a very special atmosphere as well. That's what you will get again in this match."
Doude Jamal says: "Bradford are in fine form. Arsenal will have to be on form to get anything from Valley Parade tonight. Great atmosphere."
Ellie McKinlay says: "It's good that Wenger has put a good team out because we have a good chance of going further and they have time to recover!"
Bradford come into this game on a decent run of form. They have lost just once in their last 11 games in all competitions. Former Charlton Athletic boss Parkinson has his side full of confidence and a 1-0 win over Torquay United at the weekend leaves them fourth in League Two and just three places behind the automatic promotion places.
OPTA FACT: Arsenal have made it to the quarter-final of the League Cup for the 10th year in a row, the longest ever run in the competition.
Here's a statistic for you. Arsenal have not won at Bradford in 90 years. But, hold on, they have admittedly only met twice in that time. Wenger's team lost and drew at Valley Parade in the Premier League in 2000.
Jason Farrant says: "Good to see Wenger picking a good, strong team. However, why does he continue to put square pegs in round holes?? It's been one of his biggest downfalls. Ramsey yet again picked to play in a wide position. He is a central midfielder, and I feel sorry for him getting put out wide all the time. Even so 3-1 Arsenal."
It could be a gamble for Wenger in selecting almost his strongest line-up. It is a cold night in Yorkshire when muscle injuries are a risk. Arsenal have next Monday's trip to Reading to consider. Let us not forget how difficult they found it at the Madejski Stadium in the last round of the cup, when they won 7-5 after extra time after being 4-1 down at half-time in a ludicrous game.
Gabriel Sutton says via Twitter: "Poor decision from Wenger to field most of his first team considering fatigue, but 2-0 Arsenal."
Sam is right. Bradford have a formidable record after winning their last seven penalty shoot-outs, including the win over Wigan Athletic in the last round. Wenger has said on the subject: "We have to win the game in normal time. They have gained confidence in these types of competitions, and confidence plays a big part in that. Hopefully we won't need penalties."
Sam Stevenson says: "If Bradford somehow manage to get it to penalties. WE WILL WIN. FACT."
Bradford team: Duke, Darby, Meredith, Hanson, Thompson, Atkinson, McHugh, G.Jones, Wells, McArdle, Doyle. Subs: McLaughlin, Ravenhill, R.Jones, Connell, Hines, Turgott, Good.
That is a very strong Arsenal line-up. Wenger clearly not taking any risks. Is he demonstrating his desperation to win a trophy after a seven-year drought?
Arsenal team: Szczesny, Sagna, Vermaelen, Mertesacker, Gibbs, Wilshere, Coquelin, Ramsey, Cazorla, Podolski, Gervinho. Subs: Mannone, Jenkinson, Squillaci, Rosicky, Arteta, Oxlade-Chamberlain, Chamakh.
Opposing managers Bradford's Phil Parkinson and Arsenal's Arsene Wenger know each other from days gone by. Parkinson used to do some scouting for Wenger's Arsenal earlier in his career. Wenger has said of Parkinson: "In England, when you survive in League One and League Two, you need to be good. When you survive for a long time, and you are consistent, you need to be absolutely motivated and focused. He has shown that."
Bilal Hussain says: "I think Bradford can cause an upset today, something along the line of 3-1."
Daniel Dunham says: "Think Arsenal will win 4-0 tonight. Not sure who the goalscorers will be but it's a good chance for some of our young talents to shine, should be a good game overall, good luck Arsenal."
This has the feeling of a good, old-fashioned cup tie. League Two Bradford are dreaming of a giant-killing against an Arsenal side who have not had the best of seasons so far. Can Bradford produce an upset? As we await the team news, get in touch at email@example.com or via Twitter @SkySportsPeteF. I will publish a selection of the best comments.
Hello and welcome to our live and interactive coverage of the Capital One Cup quarter-final between Bradford City and Arsenal at Valley Parade.