West Brom 1 Chelsea 0
Gareth McAuley’s late goal increased the pressure on Andre Villas-Boas – and the prospect of Chelsea failing to secure a top-four finish.
The Blues have been plagued by defensive lapses during Villas-Boas’ troubled reign as manager and their shortcomings were again exposed for West Brom’s 82nd-minute winner.
Keeper Petr Cech flapped at a corner and after Liam Ridgewell shanked a shot across the face of goal, Albion defender McAuley was on hand to poke home from close range.
It came after Daniel Sturridge had missed two excellent chances to put Chelsea ahead.
In the first half he dragged a shot wide of the target after being set up by Didier Drogba’s lovely pass with the outside of the right boot.
And after the interval Sturridge was again wasteful, this time after being put through by Juan Mata.
But Chelsea faded badly after the England man was replaced by Florent Malouda midway through the second half.
A spell of sustained Albion pressure followed, with Marc-Antoine Fortune forcing a save from Cech before Ashley Cole did well to stop Chris Brunt connecting with Ridgewell’s dangerous cross.
Ridgewell then headed narrowly over and Brunt sent a sizzling effort inches wide as the home team continued to dominate.
The deadlock was broken when Cech’s mistake was punished, with Frank Lampard and Mata then going agonisingly close to equalising.
Lampard volleyed Cole’s cross wide before Mata almost netted from 20 yards out.
The result leaves Chelsea with only one win from their last six league matches and their cause was not helped by Arsenal’s victory at Liverpool, which left the Gunners three points clear in fourth.