Aston Villa came from behind to stun Chelsea 3-1 at Stamford Bridge on Saturday and leave Andre Villas Boas' stuttering team outside the Premier League top four heading into 2012.
Didier Drogba gave the hosts the lead from the penalty spot in the 23rd minute after he was fouled by Richard Dunne, but the lead lasted only five minutes.
Stephen Ireland's first effort from Charles N'Zogbia's cross was blocked by John Terry but the midfielder tapped in the rebound to make it 1-1 at halftime.
With Chelsea fearing a fourth straight 1-1 draw, Stiliyan Petrov made matters worse when he put Villa ahead in the 83rd after being set up by Ciaran Clark and three minutes later, Darren Bent sealed his side's first win at Stamford Bridge since 2002.
Chelsea has taken three points from the last 12 and is nine points behind leader Manchester City having played a game more. The team was booed off the pitch by its own fans.
The result puts fresh pressure on Villas-Boas, who took over after Carlo Ancelotti was sacked for only managing a second-place finish last season.
The Portuguese coach conceded that the ''minimum requirement for a club like this is first place,'' and added: ''Our reality is a fourth-placed finish, but that is not good enough.
''We have to continue to pursue the best possible finish in the league, and a humble finish for this club.''
For Aston Villa, it was a first win in four games in which Ireland gave the perfect response to criticism from his manager Alex McLeish after a picture of him apparently smoking a shisha pipe was published on Twitter this week.
''He must have caught everybody's eye today. He was excellent,'' McLeish said. ''He's got to take that forward. That's got to be the standard every game.''
Chelsea sent on Fernando Torres in the second half with the score at 1-1 and the Spain striker hit the bar with a 30-yard shot, but remains without a goal since October.
Chelsea also had a penalty appeal for handball turned away before Aston Villa stole the win.
