Chelsea suffered yet another Premier League defeat as more pressure is piled on Blues boss Graham Potter.
New signing Joao Felix was sent off on his debut for a horrible tackle on defender Kenny Tete after 58 minutes while William netted against his former side in the London derby on Thursday night.
Chelsea’s performance in the opening exchanges was not immediately liberated but they were in charge in most part of the first 20 minutes.
They however fell behind in the 25th minute following a series of sloppy defending and poor organisation.
Trevoh Chalobah and Lewis Hall failed to clear their lines and the ball fell to William whose effort deflected off Chalobah into the net. Goalkeeper Arrizabalaga has no chance in saving that. The Brazilian did not celebrate out of respect.
But Chelsea levelled two minutes after the restart when Senegalese defender Koulibaly reacted quickly to poke home from close range after Mason Mount’s free kick bounced off the post.
However Carlos Vinicius scored the winner midway through the second half to hand Fulham all the three points.
Chelsea sits in an unaccustomed 10th place in the table with 25 points, 10 points adrift the top four.