Joao Felix was sent off on his Chelsea debut as Fulham beat the Blues 2-1 at Craven Cottage to heap more pressure on Graham Potter.
Willian opened the scoring against his former club on 25 minutes with a deflected shot from inside the box before Kalidou Koulibaly equalised two minutes after the restart.
Felix, who had shown plenty of bright moments having been selected barely 24 hours after completing a loan move from Atletico Madrid, then lunged in on Kenny Tete and received a straight red card.