Chelsea's amazing late fightback was ultimately in vain as Aston Villa scored a stoppage-time equaliser in a 3-3 draw which leaves the champions' Barclays Premier League title defence hanging by a thread.
Didier Drogba and John Terry looked to have snatched victory from the jaws of defeat with goals in the final six minutes at Stamford Bridge but the hosts' poor defending cost them when Ciaran Clark nodded home the first goal of his career in stoppage-time.
Both sides had held the lead in an incredible, topsy-turvy game, with Frank Lampard's penalty cancelled out by Ashley Young's spot-kick and Emile Heskey's header.
The result left Chelsea marooned in fifth place, six points behind Manchester United having played a game more.
A loss of discipline cost Villa dear, captain Stiliyan Petrov booked for a stupid lunge on Florent Malouda moments before James Collins climbed all over the Frenchman to concede a penalty. Lampard stepped up to convert his first goal since August.
And Villa's pressure told when Michael Essien's clumsy tackle on Nigel Reo-Coker handed them a penalty four minutes before the break. Young made no mistake from the spot.
Villa picked up where they had left off right from the restart. And Heskey put them ahead just two minutes in when he climbed above young Jeffrey Bruma to power home Stewart Downing's right-wing cross.
But Drogba came to his manager's rescue six minutes from time with the ugliest of equalisers. The struggling striker's miscontrol set up Salomon Kalou, whose shot was blocked back for Drogba to rifle home via Carlos Cuellar.
With barely a minute remaining, Chelsea snatched what they thought was a winner. Drogba's bullet header was parried by Brad Friedel straight to Terry, who produced a superb sidefoot finish to spark wild celebrations, with Carlo Ancelotti mobbed by his own players.
But the joy was short-lived, with Clark stealing in completely unmarked at the back post to nod in Marc Albrighton's cross.