Thanks for all your comments this evening folks! Don't forget, you can always follow me on Twitter: @RazMirza or send me your views so speak to you all soon!
FULL TIME: Real Madrid have done the unthinkable and have won at the Camp Nou! The lead over Barcelona is now back to seven points. It's Barca's first home defeat of the season and they suffer back-to-back defeats for the first time since May 2009. Sami Khedira gave Jose Mourinho's side the lead after 17 minutes but Barca hit back through Alexis Sanchez's effort on 70 minutes. However, Cristiano Ronaldo won the game three minutes later to leave with all three points and move a step closer to the title.
Meanwhile, Real Madrid have a free-kick around 30-yards out but Ronaldo fires the ball well over the crossbar.
90+2 SUBSTITUTION: Gonzalo Higuain replaces Karim Benzema for Real Madrid who has worked so hard this evening.
Great stretch from Sergio Ramos from a Barca corner although he takes a knock to the head and a free-kick is awarded.
There will be four additional minutes and four games to go in the season after this game is over.
You can't say Ronaldo doesn't come good in the big games can you? He's back on the ball and Real are in possession.
88 SUBSTITUTION: Mesut Ozil is replaced by Jose Callejon then.
Barca have won the title five of the last seven seasons and the last three in a row. Is the pendulum swinging Real Madrid's way?
86 Jose Callejon is ready to come on, but Real have this free-kick which they want to take first and it's headed away for a corner.
85 YELLOW CARD: Cristiano Ronaldo is too fast for Javier Mascherano and the former Liverpool man is booked for the late tackle.
Pepe cuts out Alexis for a corner to Barcelona and they play is short to Javier Mascherano who has a pop at goal from 30-yards, but it's high and wide.
Barca win a free-kick are want to quickly get on with the game but are dispossessed and it's four against two, but Karim Benzema opts to shoot at goal, but Victor Valdes watches it all the way.
Mazi Tweets: "I dont think Real will let this lead slip, the way Barca are playing, a draw would be a blessing for them."
80 SUBSTITUTION: Cesc Fabregas replaces Cristian Tello and Guardiola makes his final change.
At home Barcelona are unbeaten in the last 54 games and have won 11 games in a row here.
Barca win a corner and Pepe is felled by Alexis Sanchez.
77 YELLOW CARD: And now substitute Esteban Granero is booked for a late tackle on Lionel Messi.
76 YELLOW CARD: Mesut Ozil is booked for holding upthe play.
75 SUBSTITUTION: Adriano is replaced by Pedro as Pep Guardiola gambles!
74 SUBSTITUTION: Esteban Granero replaces Angel di Maria for Real Madrid.
Goal 54 of the season for Ronaldo and what a response by Real Madrid! Mesut Ozil's wonderful pass finds the former Manchester United man who takes the ball past Victor Valdes before finding the back of the net from the angle. He then proceeds to tell the Camp Nou to quieten down.
73 GOAL: Barcelona 1 Real Madrid 2 (Cristiano Ronaldo 73).
Lionel Messi runs at Real Madrid players before Andres Iniesta's flick finds Cristian Tello and although Iker Casillas makes a superb stop, the second strike from Adriano is eventually turned home by the substitute Sanchez after a scramble in the six-yard box.
70 GOAL: Barcelona 1 (Alexis Sanchez 70) Real Madrid 1.
69 SUBSTITUTION: Alexis Sanchez comes on to the field in place of Xavi.
CLOSE BARCA! He's back on the field as Barce come forward through Xavi and he whistles his shot just wide of goal.
Fabio Coentrao is in need of some attention after taking a whack to the face.
Jose Mourinho is sitting back in the dugout as Cristian Tello's cross is poor and at the other end Karim Benzema doesn't have enough strength to play a diagonal pass to Ronaldo, who was waiting in the middle for the ball.
Jordan emails in and says: "I am a major fan of Barcelona... And I'd love to see them win. Hopefully messi can pull something out the bag!"
The Real Madrid high line is working wonders, but will they eventually drop deep if it stays like this I wonder?
There have been 11 red cards in the previous 12 encounters between these sides as Messi catches Sergio Ramos and he makes thr most of the situation.
Pep Guardiola looks to his bench and may look to Alexis Sanchez or Pedro to change things.
Sergio Busquets looks for Messi, but he's coming back from an offside position.
Interestingly Barca had 70 per cent possession in the first-half and now they're starting to control the second-half as Messi's shot is well blocked.
Kieran Tweets: "I think that the way Barca are playing I think they will get one back but Ronaldo will score and settle it." Don't worry, you haven't missed anything because Pepe is on the ground rolling around in agony.
Chris Tweets: "Great game so far. This win would surely guarantee Madrid the league title, a huge knock for Barca's campaign." Absolutely spot on Chris!
WHAT A CHANCE BARCA! Thiago Alcantara's through ball finds rookie Cristian Tello in space and this time he thrashes his effort over the crossbar when he could have easily taken a touch.
Karim Benzema puts Ronaldo through and although the Portuguese star sticks the ball in the back of the net, the flag is up and he claims he didn't hear the whistle.
Messi finds young Cristian Tello who blazes his shot wide of the near post.
Luke Tweets: "I think Barcelona will come back and win 2-1 with Messi with the both of them."
That free-kick leads to a corner but Mesut Ozil's inswinger is poor and cleared easily.
Angel di Maria throws himself to the ground and is awarded a free-kick from Andres Iniesta's challenge.
Sam emails me to say: "I love seeing Barca lose, hopefully it will upset Messi and he'll change his mind about coming to England!"
The pace has picked up again as Mesut Ozil makes an important challenge. He's been working very hard tonight.
48 YELLOW CARD: Xabi Alonso makes a great challenge on Lionel Messi and referee Alberto Undiano Mallenco immediately takes his card out of his pocket. Shame!
The surface is very slick now after that downpour in the first half.
Real Madrid are singing in the rain as the second half gets underway. No changes for either side.
Barcelona have won four La Liga matches this season after trailing (in each case trailing by 1-0).
The last time Real Madrid led at halftime in a Clasico match at the Nou Camp they won the match (1-0 on Dec. 23 2007). That was also their last victory at Barcelona.
Remember, if you'd like to air your views during the second half, email Raz...that's me! at firstname.lastname@example.org or Tweet me: @RazMirza and I'll publish as many as I can.
Barcelona are now 9/4 to claim victory with SKY BET, who make Real Madrid 5/4 and the draw 2/1. My pre-match prediction of 1-1, which was 13/2, is now 3/1. Head now to www.skybet.com to place your bets.
In 218 official matches between these two sides, the head-to-head record is perfectly balanced. Both sides have won 86 encounters each and there have been 46 draws.
Barcelona are undefeated in league matches at home this season. In 16 La Liga matches at the Nou Camp in 2011/2012 they have won 15 and drawn one. Sevilla (0-0 on 22 October) were the only visitors to escape defeat so far. Barca have outscored their guests 64-8 this season in the league
HALF TIME: Sami Khedira's goal is the difference between the sides and it could also be the goal that takes Real Madrid towards the La Liga crown. Jose Mourinho has got his tactics spot on so far and are Barcelona on course for a second straight defeat in as many games? Should be an intriguing second half to come.
Just one added minute of stoppage time and this has been a pretty even fopening 45 minutes.
The rain in Spain is falling mainly on the Camp Nou right now! It's tipping it down in Barcelona and the umbrella's up everywhere.
Mesut Ozil opens up Barca and has three men in the middle but Javier Mascherano makes a vital block.
43 YELLOW CARD: Pepe is booked for a body check on Sergio Busquets.
Andres Iniesta is in need of some attention after getting the wind knocked out of his sails.
Carles Puyol wins the battle with Ronaldo and Barca break although both Dani Alves and Lionel Messi are in an offside position.
Messi finds Alves and his cross is blocked by Fabio Coentrao for a throw.
Alvaro Arbeloa does well to deny Cristian Tello any space down the left.
Ben Tweets: "Don't agree that Ronaldo is better. He'll get more space now Barca are chasing too. Barca to turn it round 2nd half!"
Messi lays the ball off to Thiago Alcantara who hits his shot from the edge of the area well wide of the mark.
The Madrid zonal marking is working wonders at the moment and is clearly frustrating Barca.
Messi has hit the net 13 times in 18 games against Real Madrid. While Ronaldo has scored in three of the last four El Clasico's.
Real Madrid have now scored 108 goals in a La Liga season which is a new single season record. And Sami Khedira's goal was his first career goal in a Clasico.
Replays of the goal show that there was clearly no handball and no offside. It was very soft defending by Barcelona who were caught out by the set play.
Referee Alberto Undiano Mallenco tells Barca to get on with the game after Messi goes to ground.
The Real Madrid game plan is working well as Ronaldo gets past Carles Puyol before firing his right-footed effort well wide of goal.
Karim Benzema finds Ozil and his long ball finds Ronaldo and now Pepe's long ball is poor.
Tello collects a lovely pass before trying to cut inside but Real manage to make the clearance.
WHAT A CHANCE BARCA! Lionel Messi plays a magic pass to Xavi, who is clean through, but he drags his shot wide of goal. Replays show Iker Casillas may have got a slight touch.
Craig emails me to say: "Mourinho magic again, hope he stays at Madrid for the next few years, could make Madrid the very best in the world AGAIN! Ronaldo once again proves he is a bigger game player than Messi. Real to win 3-2 tonight."
Xabi Alonso catches Dani Alves and the flying full-back roles around and gets his free-kick.
This hasn't been as fiesty as previous games. Remember the eye-poking, stamping, tunnel bust-ups and claims of racist taunts! The football is doing all the talking thus far!
Messi is lurking on the edge of the area, but he's soon surrounded by a number of Los Blancos players.
CHANCE REAL! Madrid are stretching Barca at the moment as Ronaldo fires his left-foot shot wide of the far post.
By the way, tonight's referee is Alberto Undiano Mallenco and he's very much an English style ref.
Barcelona look to hit back and it's all hands to the pump for the visiting side and Iker Casillas is just happy to whack the ball downfield.
Shock at the Camp Nou as the visitors take the lead and they deserve it after this opening spell. Real win a corner and Victor Valdes makes a mess at clearing Pepe's header and as Carles Puyol looks to clear his lines, Khedira quickly nips in to get a left-foot to the ball ahead of the defender and send it into the unguarded net.
17 GOAL: Barcelona 0 Real Madrid 1 (Sami Khedira 17).
15 YELLOW CARD: Sergio Busquets is booked for hacking Cristiano Ronaldo down after a superb turn of speed from the lightning quick winger.
Carlos Tweets: "Tonight Barcelona will beat Real Madrid. They're gonna win 3-1 with goals from Messi and Iniesta."
Messi's free-kick is headed away but Barca come back and Tello is caught offside.
Now Messi finds Xavi and Sergio Ramos is penalised for a late foul on the midfielder. Replays show it was 50/50!
SAVE VALDES! Karim Benzema is played on side and he gets the ball out of his feet before attempting to find the far corner, but Victor Valdes is down to make the save.
Superb pressing by Real Madrid at the moment. I've never seen a team come to the Cmap Nou and press so high!
Lee emails me to say: "Don't mind who wins this but hope mourinho has told his team to nobble a few Barca players to help out Chelsea on Wednesday!"
The visitors are pressing higher at the moment as Dani Alves gets caught offside. Lionel Messi has had very few touches up to now which is good news for Jose Mourinho's men.
CHANCE BARCA! Pepe's square ball falls kindly for Dani Alves, but Iker Casillas is out like a shot to make the save at the Brazilian's feet.
Remember, this is the same starting Madrid XI that went to Bayern Munich and lost.
CLOSE REAL! Cristiano Ronaldo comes close to scoring with a header from Mesut Ozil's corner but Victor Valdes tips the ball over the crossbar.
The Barca formation can be 2-3-5 at times while Los Blancos stick to a more rigid 4-5-1 as Ronaldo wins his side an early corner-kick.
Mesut Ozil pulls Sergio Busquets back and now Barca keep possession in the Madrid half but a long ball foward by Andres Iniesta is over hit.
Puyol wins the ball back and now the offside flag goes up. Seems as though both sides are going for it from the start. Wonderful atmosphere!
Real Madrid get the game underway and they're straight on the attack.
The teams come out to the Cant del Baraa', the Catalan Anthem of Barcelona FC which one of the most famous songs in Catalonia. Children learn it at school and parents insist they know the words. Its almost as if Catalans are obliged to learn this anthem by law!
The teams emerge from the tunnel and what a magnificent site. A mosaic around the Camp Nou...98,000 fans!
Adam also thinks it's gonna be a 4-4!! He emails me to say: "A game between the two best managers and two best clubs out there this will be a classic 4-4. I like Tello and hope he bags a couple with Messi also scoring two goals. Couldn't care less who get's Madrid's long as it's not Ronaldo!"
While Maxi Tweets: "I predict a 4-4 thriller. A Ronaldo vs Messi battle! we can hope!"
Brizo says: "Real haven't beat Barca in the league since 2008 and that's not gonna change tonight. Messi-ah will rip them to bits 4-0 Barca." Confident call Brizo!
Alistair Tweets me to say: "El clasico day is better than Christmas for me!" Do you have Turkey while watching the match then Alistair?
Kahri Tweets me to say: "2-0 madrid with benzema and ronaldo scoring!"
While, Bamidele says: "Jose Mourinho will be 'parking the bus' today and hope to have a break on Barca. As boring as that may sound, it's gonna be a smart one if they close on a draw. Gap remains 4 pts."
Qasid is first to write in today and he says: "This is Nou Camp. This is Barcelona. Of course Barcelona will it, even though they're playing Real Madrid. Real Madrid have rarely done well against the Catalan giants. If Barcelona win, they'll keep the La Liga title race alive. Messi to score a brace, one of which will be a 'wonder' goal."
Barcelona are 8/13 to claim victory with SKY BET, who make Real Madrid 4/1 and the draw 3/1. Barca's Lionel Messi is favourite to score the first goal at 11/4. The Argentine to score first and Barcelona to win 3-0 is a 28/1 shout while Xavi to score first and Barca to win 1-0 is a cool 55/1. Meanwhile, Real's Cristiano Ronaldo is 5/1 while Karim Benzema is 8/1 for the visitors. Ronaldo to score first and Real Madrid to win 2-1 a huge 50/1 shot. I'm going for a pre-match prediction of 1-1, which is 13/2. Head now to www.skybet.com to place your bets.
BARCELONA: Valdes, Alves, Mascherano, Puyol, Adriano, Busquets, Xavi, Thiago, Iniesta, Messi, Tello.
REAL MADRID: Casillas, Pepe, Ramos, Khedira, Ronaldo, Benzema, Ozil, Xabi Alonso, Coentrao, Arbeloa, Di Maria.
Here are the teams...
So, who will win tonight fans? If you'd like to air your views before or during the match, email Raz...that's me! at email@example.com or Tweet me: @RazMirza and I'll publish as many as I can.
However, another loss for Real Madrid would leave them leading La Liga by just a single point and, with tricky clashes with Sevilla and Athletic Bilbao to follow, possessing no room for further slip-ups.
This match will be decisive for the title. Can Barcelona triumph at home and cut Madrid's lead to just one point? Barcelona have cut the gap from 10 points to just four thanks to 11 successive league wins, with Jose Mourinho's men drawing three times during that run, but victory tonight will leave the capital side seven points clear with just four to play.
Guardiola added that he expected Real to press for the three points on Saturday. "They will come to win. I would be very surprised if they thought that a draw would be enough," he said. "Real have great qualities, can play defensively or on attack. They are a little like Chelsea (who beat Barca 1-0 in the Champions League in midweek), physically they are very strong and very quick on the counter-attack."
Barcelona boss Pep Guardiola admitted that defeat in Saturday's Clasico against Real Madrid at Camp Nou would crown his bitter rivals as Spanish champions. "La Liga is in Real's hands. If they win or draw, it's all over. If we want to continue to believe in our chances, then only a victory will be good enough," said Guardiola.
If you'd like to air your views before or during the match, email Raz...that's me! at firstname.lastname@example.org or Tweet me: @RazMirza and I'll publish as many as I can for this mouthwatering contest tonight.
Hello and welcome to our live minute-by-minute text commentary from this evening's 'EL Clasico' clash between Barcelona and Real Madrid from the Camp Nou.