Joao Felix was shown a straight red card for an idiotic foul on his debut as Chelsea fell to a damaging 2-1 defeat against their rivals Fulham.
The hosts went ahead before the break as ex-Chelsea star Willian found the net against his former club.
The ball fell kindly for the Brazilian in the penalty area and his effort was deflected home past Kepa Arrizabalaga.
Chelsea levelled the game right after the restart as Kalidou Koulibaly bundled the ball over the line following a free-kick from Mason Mount.
The game was turned on its head again soon after as Felix was sent off for a rash challenge on Kenny Tete. Referee David Coote had no choice but to send off the debutant following his high-footed tackle.
Fulham made the most of their man advantage as ex-Tottenham forward Carlos Vinicius headed the ball home after being found in the penalty area by Andreas Pereira.
This 2-1 win lifts Fulham up to sixth in the Premier League as they have now won all five of their games since the World Cup break.
Chelsea meanwhile remain down in tenth as they are without a win in five games across all competitions.
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