Jose Mourinho's 100th Premier League home match as Chelsea boss saw a second loss as Crystal Palace claimed their first win at Stamford Bridge in 33 years.
Chelsea secured the title with a 1-0 defeat of Palace on May 3 but the Eagles were triumphant on this occasion, stunning the hosts just when they thought Radamel Falcao had got them back into the game with his first goal for the Blues.
Joel Ward popped up to restore the lead, after Bakary Sako's opener, as Palace earned a 2-1 win - their first at Stamford Bridge since 1982.
Palace have now won eight of their 10 away matches in the league under Pardew, who has three victories against Mourinho in the last two seasons.
Mourinho played down the significance of statistics ahead of his 200th Premier League contest and 100th at Stamford Bridge, insisting three points was all that mattered.
But the Blues were unable to add to his record of 76 wins in the previous 99 home games as Palace emulated Sunderland's April 2014 success.
Mourinho may have complained of the nature of the Black Cats' success - his resentment at the officiating still lingering - but Palace were deserved winners to move second behind Manchester City.
Chelsea are eight points adrift after four points from four games.
Mourinho had said there was no "drama" after Chelsea's start, but it is clear there is plenty of work to do.
Mourinho's men have not kept a clean sheet in eight matches since winning the league against Palace and appeared porous at the back once more, with the suspended John Terry replaced by Gary Cahill.
Their next match is at Everton on September 12 and it remains to be seen which Blue shirt Toffees defender John Stones will be in.
The champions have intimated they will not make a fifth bid after a fourth offer of £37million was rejected. Everton did not confirm the offer.
Connor Wickham scored in Sunderland's win at Stamford Bridge and was included as Palace's solitary change following their victory over Aston Villa.
Palace wore black armbands due to the death of Yannick Bolasie's father. The winger returned on the bench.
The Eagles did not roll over in May and again refused to be cowed, as demonstrated by some physical exchanges, with Diego Costa often the target.
Pedro shot narrowly wide from the edge of the box before Palace had two fine chances.
Sako, the match-winner against Villa, was denied by Thibaut Courtois, who next saved when Yohan Cabaye was played in one-on-one by a fine Wilfried Zaha run.
Alex McCarthy made saves in quick succession from Costa and Cesc Fabregas, with Pedro unable to direct the third attempt goalwards.
Costa believed he was fouled in the box by Damien Delaney early in the second half. Referee Craig Pawson turned down the appeal.
Sako tried to tee up Wickham before sending Palace into the lead himself.
He stayed on his feet when Cesar Azpilicueta slid in to react to Bolasie's cross and the ball sat nicely for Sako to net.
Falcao equalised with a fine header from Pedro's cross, but Palace immediately responded.
Bolasie crossed to the back post where Sako had the presence of mind to centre the ball for Ward to head in and complete a memorable win.
TWEET OF THE MATCH
"What a proud day to be associated with @CPFC well done the manager the team and the supporters, amazing result. #cfc 1=2 #cpfc." - Former Palace striker Mark Bright was full of praise for the current players and staff after a memorable win.
https://twitter.com/Mark__Bright/status/637654832539660289 - @Mark__Bright
Thibaut Courtois: 8 (out of 10)
Branislav Ivanovic: 5
Gary Cahill: 5
Kurt Zouma: 6
Cesar Azpilicueta: 5
Nemanja Matic: 5
Cesc Fabregas: 5
Eden Hazard: 5
Diego Costa: 6
Radamel Falcao: 7
Ruben Loftus-Cheek: 6
Alex McCarthy: 9
Joel Ward: 7
Scott Dann: 7
Damien Delaney: 8
Pape Souare: 6
James McArthur: 6
Yohan Cabaye: 6
Bakary Sako: 8
Jason Puncheon: 7
Wilfried Zaha: 6
Connor Wickham: 6
Yannick Bolasie: 8
Lee Chung-yong: 6
Sako: To think the former Wolves forward was available on a free transfer this summer and Alan Pardew had to be persuaded by Palace chief Steve Parrish to sign him. Two starts, two match-winning goals for the Mali man.
MOMENT OF THE MATCH
Ward: Moments after Falcao's fine first Chelsea goal, the right-back popped up in the hosts' six-yard box to head in the decisive goal. What he was doing there, no-one knows.
VIEW FROM THE BENCH
Pardew picked a physical side who were more intimidating than intimidated. With Chelsea less than convincing so far this term, he was determined to exploit their fragility and did so. So unhappy with his defence is Mourinho that he threw on forward Kenedy at left-back. Falcao scored soon after his introduction, but Chelsea could not equalise.
MOAN OF THE MATCH
Chelsea's defeat is likely to be the focus, rather than Palace's success. There are plenty of questions for the champions to answer. Palace's first win at Stamford Bridge since 1982 was deserved, though.
WHO'S UP NEXT?
Everton v Chelsea (Premier League, Saturday 12 September)
Crystal Palace v Manchester City (Premier League, Saturday 12 September)