London - Chelsea have suffered their first defeat in 19 matches as the Premier League champions crashed 3-0 at West Bromwich Albion following the bizarre sending off of Cesc Fabregas on Monday.
Saido Berahino had given the hosts an early lead at the Hawthorns before Chelsea midfielder Fabregas was dismissed later in the first half for kicking the ball against Chris Brunt's head with play stopped.
West Brom made the most of their numerical advantage with Berahino's penalty early in the second half before Brunt got the third as Jose Mourinho's side suffered their heaviest defeat of the season and their first league loss since New Year's Day.
Although the title had been secured two weeks ago, Chelsea still fielded a strong side with Spain striker Diego Costa returning from injury after "begging" Mourinho to play him according to his manager.
With both sides having little but pride to play for, there was a jovial atmosphere inside the Hawthorns as the hosts gave the now traditional guard of honour for the champions.
It was the hosts who came first to breaking the deadlock with Callum McManaman, making a rare start for Albion, seeing his shot deflect wide from Craig Dawson's pass.
And West Brom were ahead on nine minutes as England Under-21 striker Berahino ended his nine-game goal drought by curling home from the edge of the area in superb fashion following Joleon Lescott's pass.
In response, Chelsea's Nemanja Matic fired a long range shot just wide of the post, but West Brom came close to a second when Dawson's trickery took him through the visitors' defence before his shot deflected wide.
Chelsea broke immediately with Eden Hazard seeing his effort deflect just over after a fine run from Costa.
But an off the ball clash between Costa and Gareth McAuley on 29 minutes led to an ugly altercation between players of both sides.
As referee Mike Jones went to book Costa, Fabregas inexplicably kicked the ball straight against the back of Brunt's head, prompting an angry exchange with the Albion player and then a red card for the initial offence.
Fabregas could now miss the first two games of next season if he is handed a three-game suspension.
Chelsea could have been level despite the controversy as Filipe Luis's powerful free kick was well saved by Boaz Myhill.
But West Brom were next to go close as James Morrison's slide-rule pass found Brunt, whose low effort was kept out by Chelsea goalkeeper Thibault Courtois.
West Brom started the second half in positive fashion and won a penalty in the 47th minute as John Terry brought down Berahino in the area, although the Chelsea captain escaped without a red card.
The 21-year-old picked himself up to slot the spot-kick low and hard past Courtois for his 20th goal of the season in all competitions.
Chelsea nearly grabbed a lifeline when Loic Remy's 20-yard effort had Myhill beaten, but the shot came back off the post.
Morrison's 25-yarder was tipped over the bar by Courtois but the hosts did make it three on the hour.
Brunt played a short corner to Craig Gardner who returned the ball for the Northern Irishman to drill a left footed shot that beat Courtois at his near post.
Chelsea should have got on the scoresheet when Matic was left unmarked following Luis's corner, but Myhill was able to push the ball away while Matic also fired over from a free kick to put the seal on a rare disappointment for the champions.