West Bromwich Albion almost added to their list of scalps by coming from behind to lead at Stamford Bridge before a late controversial penalty denied them the win.
The Baggies had already registered a victory at Old Trafford this season, and almost repeated the trick in West London. Liam Ridgewell's mistake allowed Samuel Eto'o to put the hosts in front, but Steve Clarke's men struck back through Shane Long and Stephane Sessegnon, before Ramires appeared to dive to win a last-minute penalty which Eden Hazard converted.
The game began in pretty poor circumstances, with Chelsea looking short of ideas in attack and West Brom unable to get a foothold in the game at all. The only time the hosts looked dangerous was through the running of Eden Hazard, although efforts from Oscar and Frank Lampard were well off target.
Chelsea hadn't looked like scoring before they took the lead, but it was once again the industry of Samuel Eto'o that got the breakthrough, as Liam Ridgewell dawdled when clearing a ball on the six-yard line after Hazard's shot was saved by Myhill, only for the Cameroonian striker to pounce and convert from close range.
That was the only significant action of a very dull first half, with the visitors unable to get themselves into the game at all. Yet after half-time, things would be different.
West Brom had been struggling to keep hold of the ball at any point of the pitch all game, but they could still pose a danger from set-pieces. So it proved when Gareth McAuley found room to plant a header at goal from a corner, and although Petr Cech parried the ball skywards, Shane Long leapt well above the Chelsea defence to nod it home before the Blues keeper could recover.
Incredibly, West Brom scored a second shortly afterwards - Chelsea felt aggrieved for a perceived foul on Branislav Ivanovic, but Steve Clarke's men broke at speed before Sessegnon hit a low effort at goal which crept under the lacklustre Cech.
The second goal spurred Chelsea into action, and West Brom were soon called into a desperate rearguard action as a goalmouth scramble ensued from a corner following Boaz Myhill's excellent save to deny Gary Cahill. Ramires, Lampard, and John Terry all came close, and the home fans were cheering on one occasion only to realise the ball had in fact merely hit the side netting, with West Brom scraping through unscathed.
Willian had a fine opportunity just after from Demba Ba's cross, but arrowed a poor header over the bar. Gary Cahill's marauding created another opportunity soon after when he stole the ball from the Baggies' defence on the right wing, but his centre was missed by Demba Ba, who was wrongfooted as he dashed into the area.
Chelsea had all the late pressure, but simply couldn't find a way through the massed West Brom defence, but suddenly Chris Brunt had a chance to secure victory as he escaped on the counter, but although he had Victor Anichebe well-positioned in support, the Northern Irishman chose to go it alone and blazed wastefully over the bar.
That was to prove costly, as Ramires charged into the box late on and pulled off a clear dive to win a penalty, going down under a shoulder-to-shoulder challenge from Jonas Olsson. Eden Hazard stepped up and coolly rolled the ball into the corner of the net to clinch a point for Chelsea, preserving José Mourinho's home record and denying West Brom another victory.
Chelsea lineup: Petr Cech, Cesar Azpilicueta (John Obi Mikel 73'), John Terry, Gary Cahill, Branislav Ivanovic, Frank Lampard (Demba Ba 64'), Ramires, Eden Hazard, Oscar (Juan Mata 73'), Willian, Samuel Eto'o
West Brom lineup: Boaz Myhill, Liam Ridgewell, Jonas Olsson, Gareth McAuley, Steven Reid, Youssuf Mulumbu, Claudio Yacob, Chris Brunt, Stephane Sessegnon (James Morrison 81'), Morgan Amalfitano, Shane Long (Victor Anichebe 78')