Osaze Odemwingie (L) celebrates with Shane Long (M), who scored the Baggies first goal
Chelsea went a fourth league game without a win as they were beaten by the top flight's surprise package West Brom at The Hawthorns, while there were big wins for Manchester City and Liverpool.
At The Hawthorns, the Baggies went in front through striker Shane Long's stooping header, reports the BBC.
Eden Hazard nodded Chelsea level but West Brom regained the lead when Osaze Odemwingie headed in Long's cross.
Chelsea were denied a spot-kick for Claudio Yacob's shove on Victor Moses and Daniel Sturridge failed to take two late chances as the Baggies held on.
Sturridge raced through on goal only to have his shot saved by Baggies keeper Boaz Myhill before he had an angled shot across goal go wide.
The almost incessant second-half pressure from the visitors failed to salvage them something from the game, while the victory moved the bouncing Baggies - managed by ex-Chelsea player and assistant manager Steve Clarke - up to fourth place and just a point behind Chelsea.
It was West Brom's sixth home league win in seven games this season.
West Brom also inflicted defeat on Chelsea at The Hawthorns last season, a loss that resulted in Andre Villas-Boas being sacked as Blues boss and Roberto Di Matteo filling the breach.
Di Matteo went on to taste Champions League and FA Cup glory so he might have had a degree of satisfaction in returning to the club who dismissed him as manager in February 2010.
In other games, Manchester City showed no mercy to Aston Villa with a 5-0 thumping exactly a week after city rivals, United came from two down to beat the ‘Villans’ 3-2, Liverpool beat Wigan 3-0, Reading came from a goal down to beat Everton 2-1, while Swansea stunned Newcastle at home 2-1 and QPR remained rooted to the foot of the table after losing 3-1 to Southampton.
Earlier, Arsenal made the best use of their one man advantage to beat city rivals, Spurs 5-2.
Arsenal 5 - 2 Tottenham
Liverpool 3 - 0 Wigan
Man City 5 - 0 Aston Villa
Newcastle 1 - 2 Swansea
QPR 1 - 3 Southampton
Reading 2 - 1 Everton
West Brom 2 - 1 Chelsea