Premier League leaders Chelsea's title challenge suffered a setback when West Bromwich Albion's Victor Anichebe grabbed an 87th-minute equaliser to snatch a 1-1 draw on Tuesday.
It looked like Jose Mourinho's side would move four points clear after defender Branislav Ivanovic, who got the winner in Chelsea's 1-0 triumph at Manchester City last week, smashed the ball home in first-half injury time to put the visitors ahead.
Anichebe, however, grabbed a precious point for the struggling hosts when he headed in Saido Berahino's cross to move West Brom out of the relegation zone on goal difference.
Chelsea now have 57 points from 26 matches, two ahead of Arsenal, who host Manchester United on Wednesday, and three clear of City, who are at home to Sunderland.
At the other end of the table, West Ham United again showed they can win without suspended striker Andy Carroll as they beat Norwich City 2-0 to ease their relegation fears with a third successive victory and fourth straight clean sheet.
Second-bottom Cardiff City missed the chance to move out of the drop zone when they were held 0-0 at home to Aston Villa while Southampton jumped to eighth with a 1-0 win at Hull City.
West Brom (Anichebe 87") 1 Chelsea 1 (Ivanovic 45+2")
Chelsea had to settle for a 1-1 draw against West Brom after dictating most of the proceedings at The Hawthorns on Tuesday.
Jose Mourinho's side proved their mettle dishing out a fine performance to outmatch the Baggies with brilliant moves from Willian and Ivanovic.
Koulossa and Amalfitano co-ordinated well but failed to get past Cahill, Azpilicueta and Ramires who read well their moves.
As the game spilled into stoppage time Chelsea got their much awaited break with Willian shooting a corner touched on by Luiz.
Ivanovic in the 45+2", who dodged his marker and turned home from close range with a right footed shot from very close range to shoot the ball to the left corner of the net.
With their title rivals all playing on Wednesday, Jose Mourinho's side could go four points clear at the top of the table with victory over the 18th-placed Baggies but things did not go as planned for Mourinho's men.
"In the last 20 minutes they put us under pressure and they scored a goal as a consequence. Maybe they deserved that point. A point is a point and at the end of the season we will see," said Mourinho.
"I think the game for 60 minutes was completely in our hands, West Brom didn't put one foot in our box. We couldn't kill the game," added Mourinho after the game.
A five-match winless streak has seen West Brom drop into the relegation places for the first time since round four of the season, and another loss would result in slipping a place lower.
Chelsea going into a 1-0 lead at half time looked as if they would pile more misery in the second half. But Pepe Mel's side endured all to reverse the tide at The Hawthorns.
The Baggies who had drawn their last two home games against Everton and Liverpool, were in the hunt for a win to avoid the drop.
Anichebe in the 87" levelled the score to knock off the shine over table top Chelsea and fought on till the end.
The Baggies looked exceptionally dangerous in the counter attack and on more than two occasions came close to finding their mark.
Chelsea having more ball possession and corner kicks failed to capitalise earlier in the game.
The referee was kept busy with Ivanovic, Cahill, David Luiz, and Willian being booked while West Brom's Yacob and Amalfitano got a yellow for dangerous tackle.
90+6" Corner for Chelsea but Foster safely collects the ball as the referee blows the final whistle.
90+5" Baggies go all out with their attack but Willian is just not giving up.
90+3" Cahill comes to the rescue to block Ridgewell who makes a dash on the counter attack into the box.
90+1" Azpilicueta looks upset as the match is halted due to injury in the Baggies squad.
90" The match now levelled hots up with both teams fighting for ball possesion and six minutes added for stoppages.
88" West Brom does another substitution. Dorrans is brought into the attack as the Baggies look for another goal.
87" YELLOW! for Matic, the fast paced game gets nasty at this stage.
86" GOAL! Mourinho's men fail to contain Anichebe who surfaces in the box to take a clever header into the net stunning the Chelsea defence.
West Brom (Anichebe 86") 1 Chelsea 1 (Ivanovic 45+2")
85" Mourinho's men attempt long shots as the clock ticks. Chelsea look in trounble in the counter attack by the Baggies.
83" Luiz and substitute Anichebe engage in a tackle resulting in a warning for Anichebe.
82" Brunt takes yet another free kick for the Baggies but the alert keeper safely collects the ball.
80" Yellow card for Luiz and Baggies earn a free kick at the edge of the box but fail to convert.
79" Baggies attack from the right flank to earn a corner.
77" More changes as Mikel replaces Oscar and the game looks well poised for a good fight at this stage.
76" Chelsea strongly defend their slender lead as Vydra replaces Thievy.
75" Yellow card for Ivanovic as the Baggies step up their attack.
73" The Baggies look good on the counter attack and earn a corner with Koulossa volleying the ball from the right but fails in his plan.
71" Morrison takes a lofted shot in front of the box which goes well over the box. The desperation beginning to show.
70" Willian has been proving too strong for the Baggies defence and on more than two occasions has completely beaten them but failed to find the target.
69" The Baggies looking to reduce the deficit with Amalfitano making a solo dash into the box but the ball is cleared away.
68" Torres replaces Eto'o making his 100th Premier League appearance for Chelse.
67 Eto'o fires wildly wide of the goal.
67" West Brom in all sorts of trouble now and battle on to keep the ball but Hazard wins it over.
66" Yellow card for Dawson for a dangerous tackle on Willian.
64" Chelsea's Willian is brought down by Ridgewell attempting to get a header in the midfield.
63" The Baggies working to a plan with Reid and McAuley making inroads and unleash the ball into the box.
61" Injured Yacob is brought out as the game continues with Mulumbu taking his place.
60" The Baggies defend solidly and push into counter attack.
59" Mourinho's men torment the Baggies with Willian once again in the thick of action.
58" Ivanovic takes a throw in with Chelsea going strong into the attack at the edge of the box.
57" Mourinho looks on from the lines as Willian makes a dash from the midfield to take a clever shot well saved under the bar by Foster who deflects it initially.
54" Ramires moves the ball once again to danger man Hazard who returns the ball Matic. Chelsea gain on ball possesion at this point.
53" Hazard on the ball makes a quick pass to Ivanovic, who taps it to Willian in front of the box but his rasping shot is well blocked by the defence.
51" Baggies earn a free kick but fail to threaten their rivals.
50" Chelsea battle on with Willian plotting the moves. Hazard is closely marked and loses the ball quickly to the defence.
49" The Baggies lose the ball to Willian who darts towards the post.
47" West Brom desperate to get open their account fight fiercely with Amalfitano and Thievy in the attack.
46" Play restarts with Mourinho's men looking stronger on the attack as Oscar is nearly gifted a goal after a feeble clearance but his shot is way off target.
45+3 Chelsea take a 1-0 lead at half time with West Brom once again struggling to find form.
45+2" GOAL! Willian takes a corner with Ivanovic making no mistake latching onto the end of a David Luiz flick to slam home into the net from five yards.
West Brom 0 Chelsea 1 (Ivanovic 45+2")
45" Oscar and Ivanovic press on and win yet another corner for Chelsea.
44" Ramires volleys the ball into the box but is headed out by Dawson.
43" Luiz and Ivanovic move the ball from the right flank.
41" YELLOW! The first card of the game is shown to Amalfatino for a foul on Hazard out on the left.
40" Hazard is strongly marked as Willian and Oscar time and again push on the attack.
38" Azpilicueta guards well an oncoming threat to pass the ball onto Ramires.
37" Chelsea build on their attack with Matic and Willian plotting moves.
36" Ramires back into the thick of action as Thievy and Berahino surge ahead into the box.
34" Ramires is brought down with an ugly challenge by Koulossa.
33" The ball put out of play for a corner taken by Willian. The ball floats over the heads of Oscar and Eto'o in the box.
32" Willian in the box looking for a cross to Ivanovic.
30" Willian moves the ball to Matic with Oscar waiting to latch on.
29" West Brom good on the counter attack put Chelsea defence on guard.
26" Willian strongly marks Brunt but is outsmarted by Reid who drills a long range shot missing the woodwork by inches.
25" West Brom attack with Brunt but the ball is snatched away by Hazard who passes the ball into the box but Eto'o fails to latch on.
24" Ridgewell takes the free kick from the centre but the ball curls onto Oscar.
22" Chelsea go close as Willian finds Samuel Eto'o with a clever ball through. Eto'o beats his man and cuts the ball back for Ivanovic but he can't force it over the line under heavy pressure.
21" A close call for Chelsea with a corner being awarded again.
20" Morrison and Brunt torment the Chelsea defence but Yacob pushes the ball out of the box.
18" A fierce battle in progress with West Brom's Amalfitano and Koulossa in the attack.
16" Ivanovic gets going with the ball spotting Luiz but Reid steps into the act with Ridgewell supporting him in the front to block the threat.
15" Neither keeper properly tested yet at the Hawthorns.
13" The West Brom boys move around the ball but fail to actually threaten the defence at this stage.
11" Hazard atempts attack from the left flank but Berahino latches onto a miscalculated pass to make dash into the box and was spotted given offside.
10" Hazard is brought down for a corner but the ball is pushed away to safety by Yacob.
9" Chelsea step up their attack with Ivanovic attempting a long shot but Koulossa blocks it.
7" Willian on the move but ball is pushed onto Cahill who returns it back with a weak pass to Eto'o in the danger zone.
5" West Brom put Chelsea under pressure for the first time in the game, but twice David Luiz snuffs out danger.
4" Chelsea on the attack with Ivanovic and Cahill passing the ball around. But fail to get past the defence.
2" West Brom's Koulossa along with Ridgewell surge ahead. But Chelsea diffuse the threat with Luiz getting on top of the ball.
The players are walking out onto the pitch at the Hawthorns where snow flakes are falling heavily.
West Brom: Foster; Reid, McAuley, Dawson, Ridgewell; Yacob; Amalfitano, Morrison, Brunt; Thievy, Berahino.
Subs: Myhill, Lugano, Anichebe, Dorrans, Vydra, Mulumbu, Gera
Chelsea: Cech; Ivanovic, Cahill, David Luiz, Azpilicueta; Ramires, Matic; Willian, Oscar, Hazard; Eto’o.
Subs: Cole, Lampard, Torres, Mikel, Schürrle, Salah, Schwarzer
Fernando Torres is ready to return for Chelsea's Premier League visit to West Bromwich Albion on Tuesday, manager Jose Mourinho told a news conference on the eve of the game.
Spain striker Torres has been out for three weeks with a knee injury.
Fernando Torres is back available but likely to sit on the bench as he rebuilds his fitness after a knee injury.
Mourinho may be tempted to rest a few players with the weekend's game in mind, with Matic perhaps dropping to the bench at the expense of Ramires.
As for the Baggies, West Brom are comfortably sliding back into mid-table after a tricky start and Mourinho’s former assistant manager Steve Clarke has put the Midlands club back on course.
A win at Manchester United and a draw at home with Arsenal in the past few weeks has shown that WBA can hang in with the big boys, and the emergence of youngster Saido Berahino has given Clarke’s team a massive boost.
Both Berahino and new signing Thievy had an impact from the bench at the weekend and could line-up on the wings on Tuesday.
Pepe Mel substituted Liam Ridgewell at half time against Palace but will surely stick with a conventional back four against opposition of Chelsea's quality.
With Anelka still sidelined and Vydra failing to impress thus far, Anichebe should keep his place in the side.
Chelsea have now been reinstated as favourites to win the Premier League having moved to the top of the table for the first time this season.
The Blues have kept clean sheets in their last four away matches in the league and face a West Brom side that are yet to win under the stewardship of Pepe Mel.
Though the Baggies have struggled to convert draws to wins this season they've proven to be a tough nut to crack for the big teams, taking points off of 7 of the top 8 sides this season.
West Bromwich Albion
Having failed to beat Chelsea West Brom have won their last two matches against the Blues at The Hawthorns.
They have lost just one of their last four games against the Blues.
The 2-2 result between the sides was the first time they squared off.
West Brom are winless in four matches and have won only one of their last 15 league games.
The Baggies have kept just three clean sheets in their last 22 league games at The Hawthorns.
Chelsea have earned 26 points out of the last possible 30 and have a clean sheet in nine games.
They conceded six goals fewer than any other side in the Premier League this season.
Eden Hazard has 12 top-flight goals this season, three more than he managed in the whole of 2012-13.
The Blues have scored 11 goals from outside the box in open play this season in the Premier League, more than any other side.