Cahill can't get a shot away but it doesn't matter. The final whistle goes and Chelsea are throught to the fifth round of the FA Cup.
Chelsea counter from the corner and win one themselves thanks to Hazard's run.
Brentford threaten to score a consolation and Luiz is forced to hit the ball behind for a corner.
Four minutes to be added at the end of the match.
Cahill is fouled by Donaldson.
Free kick just inside Chelsea's half now for Brentford.
The tempo has slowed down as you might expect with the win in the bag for Chelsea.
Brentford are currently playing with 10 men as Reeves has his jaw looked at.
Luiz is booked for a nasty challenge on Reeves. After a second look, he is lucky not to be dismissed as he seems to deliberately guides his shoulder onto Reeves' jaw.
The goal came from that corner as the ball came to Oscar on the left edge of the box. He cleverly creates enough space to put a cross in and it is an excellent delivery for Terry to head in at the far post. 4-0 and comfortable now for Chelsea.
It is Bertrand who has come on for Lampard.
GOAL - Terry scores on his return to the team!
Oscar does really well to beat Dean to the ball before passing to Lampard in style. Lamps wins a corner before being subbed off.
Lyn writes: "Seems the boys are trying hard but maybe Chelsea got a good talking to at half time and have uped their game. Hope the Bees can get one back."
Forshaw, who caught the eye for Brentford today, is being replaced by Saunders as the visitors make their final change.
Brentford are having a good spell of possession in their own half but they don't look like making anything of it and lose the ball once entering the hosts' half.
Chelsea make a substitution now, Benayoun is coming on for the outstanding Mata.
Donaldson does well to keep the ball in on the left wing. He plays it back to Bidwell but his cross is ineffectual and Cech easily gathers.
Reeves has come on for Diagouraga.
A quickfire double from Chelsea as Lampard makes it 3-0. Not long after Donaldson had gone close with a header from a Brentford corner, Lampard is left with an easy finish after a superb assist from Mata. He made a lengthy run on the left before coming in and delicately chipping it across for Lampard to hit home.
GOAL - Lampard finds the net!
Ivanovic recieves the game's first yellow card.
Diagouraga plays a poor pass in midfield and Chelsea capitalise. Hazard feeds Ivanovic on the right. The Serb runs to the byline before pulling it back to Oscar, who flicks it inventively towards goal. It takes enough of a deflection to prevent Moore grasping it. Should be game over now.
GOAL - Oscar makes it 2-0!
Brentford have an attacking throw on the left wing. The ball is hit towards Donaldson but he can't keep it in play. Goal kick.
Chelsea make a switch now. Hazard is replacing Moses.
Logan pushes Mata in the back to hand the hosts a free kick in their own half.
Chelsea deal with the corner. They have to be a little careful now as they only have a goal lead and Brentford are looking determined.
Chelsea win a corner. Cahill gets his head to it but Brentford clear. Donaldson then wins the ball in midfield to give the Bees a great chance to counter. He tries to slip in Forrester but the pass is overhit and his strike partner does well to earn a corner in the end.
Logan is now forced to head out for a throw on the other side, with Cole threatening to recieve a high pass.
Bidwell watches Moses all the way before sliding in to put the ball out for a Chelsea throw on the right side of midfield.
Good work rate by Adeyemi to force a corner for the visitors. The ball comes in but Craig struggles to keep it in play.
Brentford have made a change, Forrester coming on for Trotta.
Donaldson threatens at the other end but he waits too long before shooting at goal and hits the side-netting.
For all their efforts of working the ball into the box, Chelsea's goal comes in the simplest of ways. Cech pumps the ball forward, Ba challenges in the air and the ball falls to Mata. The Spaniard takes a touch to get the ball out of his feet and fires into the bottom right corner. Great finish.
GOAL - Mata scores!
Brentford waste possession with an aimless punt forward from midfield.
Douglas and Dean are the defensive heroes as they eventually get the ball clear from Oscar's original corner.
Mata's free kick is headed clear but it is not long before Chelsea are back on the attack. Moses wins a corner with some good work on the right.
Oscar makes a good run down the left before coming inside and into the box. His lay back is weak though and Brentford clear but then concede a free kick, providing Chelsea with a crossing opportunity.
Mata delivers well following a short corner but Brentford clear temporarily. Chelsea come back with Oscar who whips in a dangerous cross but Moore makes a great save from a header and Ba can't reach the ball to rebound it in.
Ivanovic plays a one-two with Luiz before charging down the right. He doesn't get a cross in and the ball is passed to Luiz, who does well to win a corner.
Chelsea attack with Cole on the left. He tries to feed the ball to Lampard but Logan tackles well, knocking the ball off the England international for a goal kick in the process.
Brentford get the second half underway.
Lyn writes: "Am on a train heading back to London from Scotland, hubby is ardent Brentford fan at the big match and he says its a good game . Would be fantasy if we could beat Chelsea! I know the boys are trying hard. Come on you BEES!"
Half time priceboosts include Oscar, who hit the post in the first half, to score next at 9/1 and the scoreline to stay the way it is at 7/1. Chelsea have struggled to transfer their dominance into goals and Brentford have had their moments so if you fancy a wealthy return from your money, why not back the visitors to win in extra time - available at 40/1!
Despite not making the first half their own, Chelsea are still heavy favourites to win the match. They are priced 2/7 while Brentford are very much unfacied at 12/1 despite the fact they perhaps should be in front at the break. The draw has been reduced to 3/1.
Still goalless at Stamford Bridge but it has not been a bad game to watch at all. Chelsea have had several chances but on the whole have found it difficult to break down an organised Brentford backline. For the visitors, they will be devastated at the decision not to allow Trotta's goal, with the referee awarding them a free-kick instead. Plenty to discuss so get your opinions in to firstname.lastname@example.org.
The corner is cleared and there is no further action before Swarbrick blows for half time.
At the other end, Adeyemi is charged down before he can really get a shot away and Brentford have a corner. Just a minute to be added to the first half.
Lampard spurns a good opportunity for Chelsea to take the lead as he scuffs wide.
Cahill shows his awareness by helping out Ivanovic to clear the ball from Donaldson after Douglas had hit a dangerous pass behind the defence.
Good idea from Mata but his attempted pass for Moses is slightly wayward and Moore can gather.
Oscar and Diagouraga both fly into a challenge deep into the Brentford half but it is the Chelsea man who is penalised.
Forshaw's effort is blocked along with his second attempt. Brentford will feel aggrieved by that decision from Swarbrick.
Trotta puts the ball in the net for Brentford but the have to settle for free kick just outside the area as the referee had alreadly blown his whistle for a foul by Luiz on Forshaw.
Lampard slips as he takes it and Brentford are able to deal with it.
Free kick for Chelsea on the left edge of the box as Cole looks to overreact from a Logan challenge. Lampard is standing over it.
Both teams play a few sloppy passes before the ball finds its way back to Chelsea who again are patient as they struggle to find space.
Luiz wins the ball well with a crunching challenge on Forshaw.
Forshaw sees a good effort touched wide by Cech. Brentford can't make the corner count, however.
Good defending by Douglas meet Luiz's cross before Ba could. The ball goes loose and Moore gratefully smothers.
Ivanovic completely misses the ball with an attempted vollyed pass but Cahill covers him to win back the ball for the hosts.
Donaldson does well in his own half to dispossess Moses.
Mata tries to land a free kick into the area but Brentford get it clear - for now.
Brentford try to counter but a switched ball across the pitch is just overhit and Chelsea get a throw.
Cole charges down the left flank but Adeyemi is able to block his attepted pass inside.
Oscar hits the post! A clever flick from Ba leads to some good link up play between Oscar and Mata but the Brazilian hits the outside of the right post with his effort.
No goals yet but Chelsea are beginning to pile on the pressure.
Ba and Oscar link up well before Mata curls in a teasing low cross into the box. Ba can't quite reach it and Cole spoons his effort high at the far post.
Tame appeals for a penalty as Donaldson uses his strength to deny Ivanovic reaching the ball before it runs out for a goal kick.
Chelsea stay on the attack but Lampard wastes a good opening by shooting over.
Oscar tries to create space in the box for a shot but Douglas gets a foot in. Luiz tries to keep the attack alive for Chelsea but his low cross is cleared into touch.
Brentford seek to make Chelsea pay but Forshaw's shot, which looks to be heading on target, is blocked by his own team mate.
The resulting corner comes to nothing for the hosts.
Should be 1-0. Oscar and Moses are skillfull in the build up before the latter pulls it back for Lampard. The veteran midfielder can't get his shot away and it falls to Oscar, who sees his effort deflected behind be Dean.
Chelsea just controlling possession at the moment without threatening.
Mata delivers and Brentford struggle to get it clear. Oscar whips the ball back into the box but Ba gets his header all wrong and doesn't trouble the Moore's goal.
Corner now for Chelsea as they look to break the deadlock.
Douglas is penalised for a high foot on Mata.
Chelsea seem prepared to be patient and keep possession in their own half until some space opens up.
Logan puts in a good cross from the right for Donaldson but the Brentford striker can't direct his header on target.
Ivanovic goes close with a header from the delivery but it goes narrowly over. Maybe should have done better considering how badly he was marked.
Good skill by Moses draws a foul on the right wing.
Forshaw turns quickly in midfield and goes for goal from outside the area. Not an awful effort but it goes harmlessly wide.
Terry searches out Mata with a long ball forward but it is hit too hard and travels out for a goal kick.
Chelsea have enjoyed the lion's share of possession so far but have yet to create a clear-cut opportunity.
Brentford try to work the ball forward on the right but Adeyemi is caught offside as he looks to recieve the pass from Diagouraga.
Oscar wins the ball for Ba but the striker's shot is blocked.
Oscar's cross is deflected goalwards but Moore catches the ball and just about keeps it from crossing the line.
Free kick for Chelsea on the right wing as Bidwell fouls Moses.
Forshaw tries a run in midfield but is stopped in his tracks by a Luiz challenge.
Chelsea keep hold of the ball in their own half for the opening moments.
Chelsea kick us off.
Scott writes: "I'm going for a comfortable 4-1 win for chelsea, I think lampard will score 2 while Ba and Moses will finish off. Brentford will open up the scoring though."
Toby writes: "Hi, it's Toby here! Supporting CHELSEA today as always!!! Ba to score at least! My prediction is 3-1!"
Juan Mata is having a great season so far for Chelsea and should have a few chances today. You can get 5/1 on him opening the scoring in one of several priceboosts before kick-off. Visit www.skybet.com to place your bets.
The odds indicate Chelsea should have no problem in maintaining their record of having reached the FA Cup fifth round in all but one of the last 14 years. They are as short as 1/7 to win today, with Brentford all the way out to 14/1 and the draw available at 7/1.
Neil Swarbrick is in charge of proceedings today. We've got just under 20 minutes until kick-off.
Here is how the teams line up this afternoon..
Chelsea: Cech, Ivanovic, Cahill, Terry, Cole, Luiz, Lampard, Oscar, Mata, Moses, Ba. Subs: Turnbull, Ramires, Torres, Hazard, Azpilicueta, Benayoun, Bertrand
Brentford: Moore, Logan, Craig, Dean, Bidwell, Adeyemi, Diagouraga, Douglas, Forshaw, Donaldson, Trotta. Subs: Lee, Barron, Saunders, Hodson, Forrester, Reeves, Hayes
Email your thoughts and predictions on the game ahead to email@example.com and I will try to publish them. Team news coming right up..
Hello and welcome to coverage of the Fa Cup fourth round replay between Chelsea and Brentford at Stamford Bridge. It finished 2-2 in the original tie, with a late Fernando Torres strike salvaging a replay for the Blues. Could we be in for another shock in the competition today following Blackburn's victory over Arsenal and Oldham's last-gasp draw with Everton yesterday?
Kick-off is at 1200 GMT...