Victor Anichebe pegged back a Premier League high-flier for the second successive home game as West Brom drew 1-1 with Chelsea.
The league leaders looked set to extend their advantage at the summit to four points after Branislav Ivanovic – as he did eight days ago at Manchester City – gave them a first-half lead.
But the Serbian defender's contribution would not prove decisive on this occasion as Saido Berahino's 87th-minute cross was glanced home by substitute Anichebe, who also ensured a share of the spoils when Liverpool visited The Hawthorns last weekend.
Arsenal and Manchester City can both leapfrog Jose Mourinho's team with wins in their respective games against Manchester United and Sunderland on Wednesday night, while West Brom edge out of the relegation zone ahead of the latter club on goal difference.
Thievy Bifouma marked his West Brom debut at Crystal Palace on Saturday with a goal less than a minute after coming on.
The on-loan Espanyol forward was rewarded with a first start, one of four changes made by Pepe Mel, and faced up to a Chelsea defence still lacking John Terry due to a muscle strain.
There was little to unduly concern either backline in the opening 20 minutes, although Chelsea had established a controlled hold on possession.
In the 22nd minute, Willian found Samuel Eto'o inside the area and his cutback was scrambled away from the onrushing Ivanovic by a combination of Gareth McAuley and goalkeeper Ben Foster.
West Brom grew impressively into the game and Chris Brunt fizzed a low drive wide after Bifouma failed to control Berahino's knockdown.
A succession of Chelsea corners came to nothing until their final set-piece of the half – in the third minute of stoppage time – was touched on by David Luiz and his defensive colleague Ivanovic slammed home unmarked.
Foster made a sharp stop from Eto'o when the former Barcelona striker collected Willian's 50th-minute throughball.
The West Brom goalkeeper bettered that save as the hour approached, adjusting to keep out Willian's deflected shot after his defence backed away from the rampaging winger.
Eden Hazard beat the West Brom offside trap in the 68th minute and teed up Eto'o, but his final contribution before being replaced by Fernando Torres was to slash wide of the near post.
Emboldened by their visitors' profligacy, West Brom mounted considerable pressure in the final quarter of an hour – Bifouma and Brunt both pulling attempts off target from inside the area.
McAuley then rose unmarked to meet Brunt's 81st-minute corner and could not direct his header downwards.
But the pressure told as Anichebe found a way through and, when Torres left the field at full-time amid a heated confrontation with Foster, it was indicative of Chelsea's feelings towards an opportunity missed.
|Walker juggles music, football careers in Sweden|
|Song to face ´brother from another mother´ Fabregas|
|Adriano announces Le Havre deal|
|Pardew braced for Old Trafford test|
|Lescott unfazed by City reunion|
|Tskhadadze appointed Georgia coach|
|United to finish top three - Ferdinand|
|Allardyce: Stamford Bridge stalemate saved my job|
|Southampton need three January signings, says Watson|
|Liverpool can make Champions League, says fanzine editor|
|Walsh: Hull clash crucial for Leicester|
|Toure, Aubameyang and Enyeama make shortlist for African gong|
|Docherty backs Chelsea to win two-horse race|
|Liverpool could benefit from Hyypia influence - Scales|
|Saudi Arabia name Asian Cup squad|
|Forty-year-old Cahill no problem for Postecoglou|
|Wenger criticism baffles Redknapp|
|Leicester must strengthen in window - Walsh|
|United not title contenders - Docherty|
|Koeman: Southampton youngsters will get a chance|
|Dyche empathises with Liverpool striker crisis|
|Cagliari turn to Zola|
|Rooney thanks Van Gaal for Christmas break|
|Cruzeiro offer Paulinho Tottenham exit chance|
|Carlisle´s wife grateful to Burnley|
|Katebe called up to Zambia AFCON squad|
|Cape Verde name AFCON squad|
|Finke names much-changed Cameroon squad|
|Grant omits World Cup troublemakers for AFCON|
|Blackpool striker Ranger goes AWOL|
|Allardyce relishing Mourinho meeting|
|Ashley fails to increase Rangers stake|
|Crystal Palace v Southampton: Koeman calls for focus|
|Warnock targeting striker in January|
|Chelsea v West Ham: Adrian vows visitors will attack|
|Heskey signs short-term deal at Bolton|
|Everton v Stoke City: Martinez eyes strong form|
|Juninho defends David Luiz|
|Burnley v Liverpool: Dyche defends Rodgers ahead of Turf Moor test|
|Arsenal v QPR: Wenger eyes festive momentum|
|Liverpool are growing in confidence, says Rodgers|
|Redknapp: Austin future could depend on survival|
|Martinez wants Everton consistency|
|Barca want Neymar until 2020, says agent|
|Jones undeterred by pressure of Liverpool starting role|
|Allardyce ´knows how to beat managers´ - Carroll|
|Jones playing for a new contract|
|China select Evergrande spine for Asian Cup|
|A-League Preview: Koren tips City to build|
|Khedira keen to fight for Real spot|