Sunderland - Two goals in the space of three minutes midway through the second half, including a winner by the prolific Jermain Defoe, clinched a 3-2 win for Sunderland over Chelsea as the Black Cats moved out of the Premier League relegation zone on Saturday.
After Diego Costa and Nemanja Matic had scored, either side of Wahbi Khazri's superb equaliser, to hand visitors Chelsea a 2-1 half-time lead at the Stadium of Light, Sam Allardyce's team equalised for the second time in the 67th minute when Fabio Borini turned in Patrick van Aaanholt's left-wing pull back.
Worse was to follow for Chelsea just three minutes later, with goalkeeper Thibault Courtois again only able to help a shot into the net, this time from Defoe.
DeAndre Yedlin attacked energetically down the right and his cross was helped into the path of Defoe by John Obi Mikel and the forward struck his 15th goal of the season from 12 yards.
To compound matters for the London club, Chelsea captain John Terry was dismissed late in injury-time for a second bookable offence following the central defender's foul on Khazri.
If Sunderland win at home to Everton on Wednesday, they will stay up and relegate both Newcastle United, their arch north-east rivals, and Norwich City in the process.
Costa opened the scoring after 14 minutes with an impressive finish from a wide angle after Gary Cahill had enjoyed a fortunate bounce off defender Yedlin and the ball broke kindly for the Chelsea forward.
The lead lasted until four minutes before the interval when Mikel headed clear a Yann M'Vila free-kick, Lamine Kone returned the ball into the visitors' area and, after Cahill nodded to the edge of the box, Khazri sent a spectacular 20-yard, right-foot volley flying into the back of the goal.
But Sunderland's defence then gifted Chelsea a second goal in the third minute of added first-half time.
Cesc Fabregas's speculative punt forward was headed on by Cesar Azpilicueta and Matic, who had scored just twice before in his Chelsea career, slipped the ball under the advancing Vito Mannone.
Chelsea weathered a spirited start by Sunderland and, with Eden Hazard and Fabregas increasingly influential, continued where they had left off in the second half of Monday's 2-2 draw with second-placed Tottenham Hotspur that assured Leicester City of the Premier League title.
After nine minutes, Hazard pulled the ball back for Willian whose low shot was straight at Mannone and shortly after, a darting run to the by-line by Fabregas ended with a dangerous cross which was well defended by Kone.
That was part of a passage of play that included Hazard sparking the move that led to Cahill setting up Costa for the opener and, given their record of not having beaten Chelsea at home for 16 years, Sunderland appeared in trouble.
Sunderland had a glimmer of hope as Yedlin started a move which ended with Defoe crossing to the far post where the full-back's downward header was blocked by Courtois.
But, in a swift response, Costa came within inches of doubling his and Chelsea's tally as he slid in to try to meet Branislav Ivanovic's low cross, just failing to make contact in front of an open net.
Costa might have wrapped up victory for Chelsea early in the second half, following a defence-splitting pass from Hazard, but he shot directly at Sunderland goalkeeper Mannone.
The Spain international was guilty of a similarly bad miss just after the hour when Fabregas and Hazard combined to play him into an unmarked position only for the striker to hurry his shot straight at Mannone.
The key Sunderland goals soon followed and, while Mannone had to make an excellent one-handed save to keep out a Willian free-kick in the 74th minute, there was little else to trouble the home side.