Debutant Joao Felix's red card proved costly as Carlos Vinicius earned Fulham a 2-1 win over west London rivals Chelsea that piles even more pressure on head coach Graham Potter.
Joao Felix was named in injury-hit Chelsea's starting line-up, a day after joining on loan from Atletico Madrid, and saw red for a lunge on Kenny Tete shortly before the hour mark.
Chelsea had fought their way back into the match at the time of that dismissal after Kalidou Koulibaly's close-range finish cancelled out former Blues winger Willian's first-half opener at Craven Cottage.
Fulham were without suspended top scorer Aleksandar Mitrovic, but Carlos Vinicius headed in his first Fulham goal in the 73rd minute to land his side a rare win in this fixture and make it six defeats in eight for Chelsea.
1 - João Félix is the first player to be sent off for Chelsea on their Premier League debut, and the first to do so for any club since Federico Fazio for Spurs vs Manchester City in October 2014. Welcome. pic.twitter.com/iRDENxeSLV— OptaJoe (@OptaJoe) January 12, 2023
Bernd Leno did well to keep out an early Lewis Hall strike in a bright start from Chelsea, with Joao Felix looking particularly lively in the final third.
Fulham soon grew into the game and struck the crossbar through a powerful Bobby Decordova-Reid effort, shortly after Carlos Vinicius had a penalty shout rejected.
However, Willian gave Fulham the lead when Chelsea's defence backed off and allowed the winger to fire away a shot that deflected off Trevoh Chalobah on its way through.
Leno continued to frustrate Chelsea, but he was almost caught out by a Mason Mount free-kick that struck the right-hand post and landed nicely for Koulibaly to squeeze over the line.
Chelsea lost another player to injury when Denis Zakaria hobbled off and then had Joao Felix dismissed for a studs-up challenge on Tete.
More misery was to follow for Chelsea and Potter as Andreas Pereira played in a delightful cross for Carlos Vinicius to get above Chalobah and power home a winning goal at the back post.