Bobby Zamora struck an injury-time winner as Fulham stunned 10-man Arsenal 2-1 to derail the Gunners' recent Premier League resurgence on Monday.
Zamora swept home the winning goal in the third minute of stoppage time at Craven Cottage after Steve Sidwell had struck an 85th-minute equaliser to cancel out Laurent Koscielny's 21st minute opener.
Arsenal paid the price for failing to capitalise on a dominant first half when they carved out a series of clear chances only to be denied by some superb keeping from David Stockdale.
Fulham's grandstand finish came after Johan Djourou was sent off for a second bookable offence 12 minutes from time, a red card which encouraged the Cottagers to swarm forward in pursuit of an equaliser.
Furious Arsenal boss Arsene Wenger blamed his team's profligacy and refereeing decisions for the defeat.
"We missed many chances and had some bad decisions from the referee today. The two together made the difference," Wenger said, decrying Djourou's dismissal as a "joke."
"I felt the referee got it all wrong," he said. "It's very difficult to swallow because I don't think we deserved to lose today."
The defeat was only Arsenal's second reverse in 13 games and saw Wenger's men drop down to fifth after Chelsea scored a dramatic late win at Wolves, Frank Lampard striking an 89th-minute winner in a 2-1 win.
A feisty encounter saw Chelsea take the lead through Ramires on 54 minutes, and Chelsea's players celebrated by racing over to embrace under-fire boss Andre Villas-Boas in a show of support for the Portuguese manager.
However Wolves looked to have grabbed a share of the points when Stephen Ward struck six minutes from time only for Lampard to rescue Chelsea at the death.
"It's a massive win. Everyone knows we are having a tough time but the determination shone through and I think we deserved it," Lampard told the BBC. "The character showed as we battled through to the end and that is what the players are all about."
Villas-Boas meanwhile refused to single out Lampard for praise.
"The players were magnificent today, no matter who scores," Villas-Boas said. "It's a good solid team win."
Elsewhere, Blackburn were brought down to earth following their away win over Manchester United at the weekend after suffering a 2-1 defeat to Stoke at Ewood Park, Peter Crouch scoring twice for the visitors.
Blackburn looked to have got off to a dream start only for Christopher Samba's early effort to be ruled offside.
Stoke then went ahead with Crouch netting his 100th league goal from close range after Blackburn failed to deal with Dean Whitehead's chip forward.
Crouch then doubled Stoke's lead with his second of the match on 45 minutes to leave Rovers staring at their eighth home defeat of the season.
David Goodwillie scrambled one back in the 69th minute to give Rovers hope but the home side were unable to find an equaliser.
Aston Villa's feelgood factor from their win at Chelsea was also shattered, with newly promoted Swansea scoring a 2-0 win at Villa Park.
Swansea went ahead after only four minutes, Nathan Dyer punishing some slack defending from Stephen Warnock to dart forward and finish past Brad Guzan.
Former Villa old boy Wayne Routledge then doubled Swansea's lead two minutes after the restart, punishing a poor clearance from Guzan after Danny Graham's shot crashed back off the post.
QPR captain Joey Barton was hero and villain at Loftus Road as Rangers crashed to a 2-1 loss to Norwich, a defeat that edged Neil Warnock's side ever closer to the relegation zone.
Barton shot Rangers ahead on 11 minutes, drilling in a low finish from Clint Hill's cross.
But Barton's joy turned to despair on 36 minutes, when the midfielder was sent off for an apparent head butt in a confrontation with Bradley Johnson.
It got worse for Rangers moments later, Anthony Pilkington netting his fifth goal of the season to level it for Norwich.
The knockout blow from Norwich came seven minutes from time, substitute Steve Morison grabbing the winner to end a desperate rearguard action from Rangers.
Barton later accused match officials of being "conned" into sending him off.
"Well feel for the officials, they've been conned. Admitted to me at HT they never saw it. I was pulled back 1st, then kicked 2nd!," Barton wrote on Twitter shortly after the final whistle.