The home fans are already launching into song as it looks to be all three points for Clarke and his boys.
Chelsea throwing everything at it with even Cech coming up for the set-piece, the Blues goalkeeper almost booting in a possible leveller at the far post.
Blues camped inside Baggies's half and earn themselves a corner from the right.
Rosenberg makes a mild attempt on goal form the right which fails to trouble Cech.
The linesman signals four minutes of added time: can the Baggies hold on for a memorable win?
Mulumbu has been moved out on to the left flank in order to lessen his impact on the game due to his injury.
Chelsea working the flanks in an effort to stretch Albion's defensive line.
Blues maybe ruing Sturridge's miss on goal, but they continue to probe for the equaliser.
Mata and Oscar combine to feed Sturridge at the far post, but the Blues ace really should've done better with chance to draw his team level, his strike way off the mark.
All the play is taking place inside the Baggies's half of the field with the Blues relentless on attack.
Blues whipping in balls for attackers in the box from all angles, but Myhill is marshalling his troops well at the back.
Baggies doing what they can to get men behind the ball now.
Mulumbu is hoppling with what looks to be a serious hamstring injury, but Clarke's all-out of substitutions.
Ramires now on the park, Mikel having gone the other way, and immediate tries to create something going forward for the Blues
Long comes off to a standing ovation as Markus Rosenberg takes to the field for the final ten minutes.
Chelsea back on Albion's door-step, banging on the door that has Steve Clarke's men pulling out all the stops to keep the west Londoners at bay.
Mata picks out Sturridge with the Blues striker blazing towards goal, who then whips in a low drive that draws a fine left-handed parry from Myhill.
Cech hacks the ball away from his goal after another Hail-Mary pass for Long from the back.
The Baggies hoof the ball upfield with Long chasing like a man possessed.
Chelsea, again, as they throw everything at a dogged Albion back-line.
Long ball forward on the counter for Long to chase, only for Cech to gather.
The Blues keeping the game inside the Baggies's half, although as the clock winds down the home side are less afraid to work hard on defence.
Chelsea push up again, but they must be out on their feet having to now launch their attacks from deep with Albion unafraid to counter.
Baggies in the ascendency for the moment as the blues are having to make a few tackles at the back.
Moments after Mulumbu's fine strike from range at Cech, Graham Dorrans comes on for the influential Morrison as Gera also depart for Chris Brunt.
Myhill can't do no wrong right now as he gathers Mata's cheeky effort from a tight angle at the near post.
Long breaks out down the right flanks only to drift out to far and get closed down by the cover defence.
Baggies just about contain the latest barrage on their goalmouth, before looking to launch a counter.
Mata making a real impact off the bench for the Blues as he goes opn another run before trying to feed a team-mate.
Mata already making his mark, the Spaniard chipping the ball over the defence for Sturridge inside the box that Myhill just manages to parry away from the sliding striker.
Myhill, again, does well under pressure from Sturridge in the air.
Oscar and Mata come on for Oriol Romeu and Torres respectively.
Albion try to power their way out of their half, but the likes of Torres and Hazard just drive them back.
The Blues push up yet again in search of another equaliser, but the Baggies smother the movement.
Ridgewell's set-piece is hammered straight into the wall.
The crowd give a cheer as Morrison rise after receiving treatment following the hit from Cahill, as Oscar and Mata warm up for Chelsea on the sidelines.
Morrison, again, tries to weave his way through the Blues defence and draws a free-kick on the edge of the box via Cahill's robust challenge.
Morrison looking to jink his way down the left flank, with Long next trying his luck only for Cahill to clean him out legally.
Baggies working the wide channels, but the Blues aren't easily fooled and close down the space.
Myhill bravely throws himself at the feet of Moses to smother a loose ball which the Blues ace was looking to smash into the back of the net.
Long making a real nuisance of himself as the striker rise to try and meet a long ball into the box that Cech just manages to gather.
Jonas Olsson putting the hard graft for the hosts as he clears another ball into the danger area from Chelsea.
Back behind on the scoreboard, the Blues push up in earnest as the Baggies defence holds their line.
Great cross from Long out on the right sees Odemwingie head the Baggies back into the lead with a fine finish at the near post.
Sturridge and Hazard look to link up out on the right, before play is switched to the opposite flank.
Cech, again, comes out early to gather ball before Long can pounce.
Myhill and his defenders do well to withstand a flurry of shots on goal from in and around the box.
The Blues strong out the blocks as Bertrand delivers a teasing ball towards the back post for Moses that requires a clearing header from Ridgwell.
The second half is underway!
Baggies withstand a late surge from the Blues with Torres trying to sneak a boot in on a loose ball in the box.
Moses blazes his shot wide from the right when he should've maybe looked to cut the ball across the face of goal for Sturridge.
Luiz's attempt from the set-piece is deflected out for a corner, but Hazard's delivery is weak and the danger for the Baggies is averted.
Yacob flattens Sturridge that earns the Blues a favourable free-kick out on the left.
Blues utilising the flanks again with even Sturridge looking for work out wide.
Baggies now look to be sitting back and letting the Blues come at them, which may be a dangerous ploy now that the visitors have drawn level.
The tactical change from Di Matteo - Hazard out to the left - has bourne a goal and almost another as the Belgian lays the ball off for Sturridge to take another shot at goal.
Hazard heads the Blues level at the far post after Azpilicueta finds his team-mates with a good ball from the right.
Torres struggling to assert his authority in attack for the Blues as every attacking thrust right now seems to die with him.
Albion do well to contain Chelsea's latest surge, but their attempt to launch one of their own is unsuccessful.
Moses looking a bit dangerous up front as the Blues try to catch the Baggies on the counter.
Long does well to shrug off a poor challenge from Cahill to try his luck from out in front, his effort sliding wide of the far post.
The Blues force their way back into their opponents' half but they're getting closed down early.
Morrison, again, for Long inside the area with Cahill doing just enough to put off the striker's attempt on goal.
Sturridge, again, fancies a shot from range but Myhill sees the ball early and makes a reasonably comfortable save.
The match is being played just over the halfway line by the visitors, although the home side aren't shirking their defensive duties.
The Blues are getting upfield well but Hazard and Torres need to do more to hold the ball up much like Long has done for the Baggies.
Despite Luiz's attention, Long uses his upper-body strength well to hold the ball up and look to feed a team-mate.
Hazard with a run as the Belgian playmaker looks to put something together for the Blues.
Zoltan Gera almost manages to get on the end of Morrison's cross. who seems to find so much time on the ball to the ball away for his team-mates in good areas.
The Baggies push on the attack that sees the Blues put ten men behind the ball to keep the hosts at bay.
Long with an overzealous challenge on David Luiz that earns him a strong ticking off from the match referee.
Bertrand does well to cut out Morrison's pass for Long out on the right of the area.
Sturridge and Azpilicueta do well to dispossess Liam Ridgewell out on the Blues's left corner.
Gary Cahill looks to lead the charge from the back with Azpilicueta and Bertrand also pushing up with more urgency.
Blues now back in possession and probing from the middle of the park.
Youssouf Mulumbu tries to get behind Chelsea's defence out on the right, but the ball runs away from him as he races to gather the pass forward.
Baggies with some time on the ball as they carrying it up strongly into the Blues's half of the pitch.
Torres attempts a cheeky back-heel for Sturridge who was bursting into the box, but his pass is intercepted.
Moses with a shot from distance that sails out to the right of goal.
Fernando Torres makes a beautiful turn and then tries to unsuccessfully step away from Claudio Yacob, leaving the Blues striker limping after the tough tackle.
John Obi Mikel with a rare shot on goal, which is well wide of Boaz Myhill to his right.
The Blues doing well to use the width of the field as they spread their attack out the right.
Hazard finds Moses down the left wing, only for the former to fall over his own feet trying to deliver a cross into the area.
The scoreline doesn't reflect the ascendency on the attack the Blues are enjoying at the moment.
Moses, again, makes a run down the flank with Bertrand trying to feed the forward, but to no avail.
Long dives to brilliantly get on the end of a delightful cross from Morrison out on the left to give the Baggies the lead.
Victor Moses and Ryan Bertrand look to link up on the left as the Blues come again.
The home side try to strike on the counter, but the move is quickly quelled by the west Londoners.
Eden Hazard claims for hand-ball inside the Baggies's box after his shot strikes a defender's hand following a decent attacking flurry from the Blues.
Peter Odemwingie bursts down the right and tries to feed Jamres Morrison, but the ball is cleared into touch before reaching him.
Petr Cech does well to come out and get low to smother the ball from under the feet of an onrushing Long.
Daniel Sturridge with the first shot on goal of the match, an off-target left-footed effort from range.
The Blues settling in as they pass the ball around at the back looking to get a feel for the pace of the game.
A rare start for young defender Cesar Azpilicueta as he makes an over exuberant tackle on Shane Long.
The match is underway!
I think Chelsea will win 2-1. Sturridge will score but Odemwingie will equalise. Juan Mata will score a late winner. I dont think Torres should be starting. He isnt as good as when he was at Liverpool. Ibraheem Bahadur
muhammad hussain chelsea fan i supose our runof form hasnt been great in the past two wekks but anyway i am going for a 4-2 chelsea win torres hattrick hazaed to get fourth and for the baggies shane long and odemwingie
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Goalkeeper Boaz Myhill continues in goal for the hosts, with first-choice gloveman Ben Foster still on the treatment table with a groin injury. Defender Gareth McAuley failed a late fitness test after picking up a hamstring injury whilst on international duty in midweek. Midfielder Youssouf Mulumbu has recovered from a hamstring injury in time to feature. Striker Romelu Lukaku, who is on loan from Chelsea, will not be eligible to face his parent club.
Fifth place West Brom take on third place Chelsea with the draw proving popular with punters at 13/5. West Brom have won five of their last six matches at The Hawthorns and it's 11/4 they can extend that run against the European champions who are 10/11 to secure their first win in three games. Peter Odemwingie is 8/1 to break the deadlock for the Baggies, while seven of Chelsea's goals this season have come from defenders and it's 6/1 for Tim Cahill to score anytime for the Blues.
Having relinquished top spot to Manchester United a few weeks ago, Roberto Di Matteo's side have since dropped to third in the Premier League and come off the back of a 1-1 draw with Liverpool last weekend.
The fifth-placed Baggies have emerged as this season's surprise package under the guidance of Steve Clarke. They will also be in good spirits after a 2-1 triumph over Wigan last weekend saw them close the gap on the visiting Blues to four points.
Good afternoon, I'm Devin Hermanus and I'll be taking you through all the action as West Brom host Chelsea at The Hawthorns. Kick-off is scheduled for 1500 BST.