FULL-TIME: The referee brings the game to an end and Brentford have earned a replay against FA Cup holders Chelsea with Fernando Torres' late goal denying the home side a famous FA Cup win.
Donaldson has a sight of goal, but he blazes his effort well over the top and that should be that.
Strong claims for a penalty from Chelsea as Mata's cross appears to strike the hand of Dean inside the box, but the referee waves away their appeals.
The free-kick from Saunders is too deep and Turbull collects easily.
Ramires is penalised for handball. Chance for Brentford to get some numbers in the box from the free-kick.
There will be four minutes of added time at the end of the 90 minutes.
Great block from Logan just as Ramires was ready to unleash his shot.
Mata picks out Lampard inside the box, but he gets his header all wrong and it loops up into the air and into the grateful arms of Moore.
Lampard has a crack at goal from 25 yards out and Moore is alert to save the effort at the second attempt.
Brentford make their final change as Sam Saunders comes on for Forshaw.
GOAL: Chelsea draw level for a second time as the ball drops to Torres on the edge of the box and he curls a superb shot high into the corner past Moore.
Demba Ba is brought on for Bertrand as Chelsea make their final change of the game.
Big chance for Chelsea as Azpilicueta floats over a cross towards Bertrand with Moore all at sea in the Brentford goal, but the Chelsea defender cannot get his header on target.
Donaldson wins the ball out on the left and cuts inside the fires a shot off the target.
Brentford also make a change as Forrester is replaced by Barron.
Chelsea make a change as Azpilicueta replaces Ivanovic.
Great chance for Chelsea to draw level as Cahill heads Mata's corner right across the face of goal, but Terry somehow loses his balance and fails to get on the end of the ball. Chelsea keep the pressure on and Ivanovic's acrobatic overhead kick is saved by Moore.
Great pressure from Brentford as they try to push Chelsea back into their own half.
Holders Chelsea have 15 minutes to save themselves from suffering a major FA Cup upset.
GOAL: Forrester slots home the penalty and the upset is back on!
Turnbull is booked for giving away the penalty.
Brentford win a penaly as Adeyemi is brought down by Turnbull.
Trotta is replaced by Tom Adeyemi in Brentford's first change of the game.
Forshaw has a shot from 30 yards which flies high, wide and not very handsome.
Turnbull fails to collect Forshaw's corner as Brentford win another corner.
Good pressure from Donaldson on Bertrand helps Brentford win a corner.
Turnbull does well to collect Hodson's deep free-kick under pressure from Craig.
Brentford are starting to get a foothold back in the game now after being stung by Chelsea's equaliser.
Oscar works some space on the edge of the box before hitting his effort just wide of the target.
Good move from Brentford before Forrester overhits his cross straight out of play.
Lampard almost gets a free header at the front post from Mata's corner before Brentford clear through Dean.
The goal has taken the wind out of Brentford's sails with Chelsea now on top.
Chelsea have another chance as Cole gets down the left and cuts the ball back for Mata on the penalty spot, but his effort is saved by Moore.
GOAL: Chelsea draw level with a fine solo effort from Oscar and he controls the ball on the edge of the box, beats two Brentford challenges before poking his effort high into the net past Moore.
Diagouraga almost sends Donaldson in on goal, but Turnbull is quickly off his line to clear the danger.
Oscar is almost in on goal, but the ball runs through to Moore in the Brentford goal.
Good clearing header from Craig as Oscar tried to find Ivanovic inside the box.
Moore collect's Mata's free-kick wide on the right at the second attempt to ease the pressure on Brentford.
Lampard's low effort is poor and the ball breaks to Oscar on the edge of the box, but his effort is blocked by a number of bodies inside the box.
Chance for Chelsea as Torres wins a free-kick on the edge of the box. Lampard looks to be the man for this.
More good pressure from Brentford down the left as Oscar appears to be hobbling a bit.
Ramires tries his luck from 25 yards from goal, but his effort is well wide of the target.
Cole gets down the left and pulls the back for Lampard, who sees his scuffed shot blocked by the Brentford defence.
RESTART: Brentford get the second half underway hoping to hold on to their 1-0 lead.
Chelsea make a change at the break with Juan Mata replacing Marko Marin.
Bob Jackson in Cyrpus believes Brentford deserve their half-time lead and he is struggling to see how Chelsea will come back.
Richard Shirran has been shocked by Chelsea's lacklustre display and believes Demba Ba needs to come on up front to play two strikers up top.
Chelsea fan David Clark in Sydney Australia says as a proud Chelsea fan for 50+ years, I'd accept defeat against Brentford if Benitez would pack his bags and go! What do you think?
If you a fancy a bet on the outcome of the game here are the latest odds from SkyBet. Can the Bees hold on? We have cut them from 9/1 to 2/1 to progress and 7/4 to earn a replay, while Chelsea are 6/4 for a comeback win.
What does either manager need to do at the break? I look forward to hearing from you and I will endeavour to post as many of your thoughts, opinions and reaction as I can.
HALF-TIME: Brentford go into the break deservedly 1-0 in front thanks to the goal from Marcello Trotta just before the break. Chelsea have been poor all half and Simon Moore in the Brentford goal has not been tested.
There will be one minute of added time at the end of the opening 45 minutes.
Free-kick in a promising position for Brentford now. Forshaw plays the ball in low and the ball drops to Forrester and the danger is finally snuffed out. Chelsea look all at sea at the moment.
Cahill is booked for a clumsy tackle on Logan.
GOAL: Brentford take the lead as Turnbull keeps out Forrester's superb curling effort from the edge of the box and Trotta is on hand to smash home the rebound. The upset is on.
Turnbull kicks another clearance straight out of play and he has been struggling with his kicking today
Forshaw drills in a shot from the edge of the box which is spilled by Turnbull before being picked up by the keeper at the second attempt.
Torres tries to send Marin clear on goal, but his pass is terrible and it goes straight through to Moore.
Diagouraga is given a ticking off by the referee for a late tackle on Ramires, but he escapes a booking.
Shocking pass from Cahill straight out of play just as Chelsea were beginning to exert a bit of pressure on the home side.
Rafa Benitez is looking very animated on the touchline at Chelsea's performance.
Another chance for Brentford as Forrester bursts through the middle only to drag his effort off target.
Brentford go close as Logan gets in down the left and cuts the ball for Forshaw who curls his shot just wide of the target. The home side are on top here
Lampard with a free-kick for Chelsea with the big boys in the box, but his cross is poor and cleared by Brentford. Probably sums up Chelsea's performance so far.
Great play from Forrester as he slides in to win the ball before skipping past Ramires and firing in a shot from the edge of the box just wide of the target.
Marin's corner is weak and is easily cleared as Brentford try to catch Chelsea on the break.
Chelsea win their first corner of the game as Logan blocks Ivanovic's cross.
A lot of Chelsea's attacks are breaking down in the final third with some poor passing.
20 minutes gone and it remains 0-0 and Brentford will be happy with their start to the game.
Torres tries to send Betrand clear on goal, but Moore is off his line quickly to gather the ball.
Wasteful pass from John Terry sees the ball go straight to Simon Moore in the Brentford goal.
The last five minutes have been the best spell for Brentford as they put some pressure on Chelsea.
The corner is poor from Forrester and is easily cleared at the front post by Lampard.
Forrester is looking lively for Brentford and most of the home side's attack are coming down his wing as Brentford win their first corner.
Forrester has the chance to get a cross into the box, but he overhits it and is sails out of play.
The ball is teed up to Forrester from the free-kick, but under pressure the Brentford winger blazes his effort well over the top. Wasted chance for the home side.
Big chance for Brentford as Terry is penalised for a backpass to Turnbull so it will be a free-kick inside the box for the home side.
Trotta has Brentford's first shot of the game, but he slices his shot well wide of the target, but encouraging from the home side.
Good pressure from Douglas on Turbull sees the Chelsea kick the ball straight out of play. Douglas wins a great cheer from the home fans.
Brentford seem content to let Chelsea have hold of the ball as the visitors look to break down the home side.
Oscar has a sight of goal on the edge of the box after picking up a pass from Marin, but he drags his shot off the target.
Chance for Chelsea as Cole gets down the left and fires over a cross right across the face of goal, but Torres can't get on the end of it and the opportunity goes abegging.
Great atmosphere inside Griffin Park with Chelsea enjoying some possession in the early stages.
Early scare for Brentford as Torres wins a flick on from Ivanovic's long throw, but no one is on the end of it to have a shot at goal.
Kick-off: Chelsea get the game underway in front of a full house at Griffin Park.
Ryan on Twitter is predicting a tight game with Chelsea coming out on top 1-0 with Fernando Torres netting the winner.
Jamie Sadler via Twitter is going for a 3-0 win for Chelsea with Oscar, Marin and Torres scoring for Chelsea
What are you score predicitions for today then?
Chelsea are the overwhelming favourites at 1/4 with Brentford 9/1 to win and 5/1 to earn a replay. Fernando Torres starts and is 100/30 to score first, while Clayton Donaldson represents the Bees' best chance of netting at 7/2 anytime.
If you fancy a flutter on today's game check out the latest odds with our betting partner SkyBet.
I look forward to hearing from you and I will endeavour to post as many of your thoughts, opinions and reaction as I can.
If you would like to get in contact at any point this afternoon then please don't hesitate. You can mail me via the Score Centre, email me direct on peter.o'rourke @bskyb.com and you can also now Tweet me: @skysportspeteo.
Chelsea XI: Turnbull, Ivanovic, Cahill, Terry, Cole, Ramires, Lampard, Marin, Oscar, Bertrand and Torres
Brentford XI: Moore,Logan, Dean, Craig, Hodgson, Douglas, Diagouraga, Donaldson, Forshaw, Forrester, Trott.
The teams are in...
Welcome to our minute-by-minute commentary of Brentford's FA Cup clash against Chelsea from Griffin Park.