Fulham increased the pressure on Chelsea boss Graham Potter with a shock 2-1 victory that saw Blues forward Joao Felix sent off on his debut before a decisive blunder from Kepa Arrizabalaga.

Potter's troubled side crashed to a seventh defeat in their last 10 games in all competitions after another spluttering display.

Chelsea fell behind to a goal from their former winger Willian in the first half at Craven Cottage on Thursday.

Kalidou Koulibaly equalised after the break but Felix was dismissed for a reckless studs-up lunge on Kenny Tete.

Fulham were gifted their late winner by Chelsea keeper Kepa, who made a hash of dealing with a cross that Carlos Vinicius converted to leave Potter facing renewed talk of the sack just four months after he replaced the axed Thomas Tuchel.

Potter this week labelled managing Chelsea as "the hardest job in football" after a turbulent period that is severely testing owner Todd Boehly's hope that the former Brighton boss is the right man for the task of leading the new era at Stamford Bridge

Chelsea are languishing in 10th place -- 10 points adrift of the top four -- after their wretched run extended to one win in their last nine league games.

They have managed just four goals in their last eight games in all competitions and Potter desperately needs a victory against Crystal Palace on Sunday to buy himself at least a little breathing space.

Hampered by a debilitating injury list that includes N'Golo Kante, Christian Pulisic, Raheem Sterling, Ben Chilwell and Reece James, Potter admitted this week that Chelsea have been "suffering".

The 47-year-old held a meeting with senior players Cesar Azpilicueta, Thiago Silva, Jorginho and Mateo Kovacic on Tuesday in an attempt to calm the crisis.

But Chelsea fans' patience is already wearing thin and losing to sixth placed neighbours Fulham was another bitter blow to his hopes of avoiding the sack.

It was in keeping with Potter's misfortune that Felix's promising debut ended prematurely after his loan move from Atletico Madrid on Wednesday.

The 23-year-old, who cost Chelsea a reported 11 million euros ($12 million) loan fee, was one of four changes from the 4-0 FA Cup defeat at Manchester City last weekend.

- Potter misery -

Given license to roam across Chelsea's three-man attack, Felix showcased his speed and agile footwork as he surged into the Fulham area.

Felix's pass found Kai Havertz and when the German's shot was blocked, he laid the rebound to Lewis Hall, whose low drive was saved by Bernd Leno.

Picked out by Mateo Kovacic, Felix fired wide from the edge of the area, then volleyed over after Azpilicueta's cross found him unmarked 10 yards from goal.

Despite that bright start from Chelsea, Potter's defence was vulnerable.

Fulham's Bobby De Cordova-Reid slammed his shot against the bar after a careless header from Trevoh Chalobah.

And Potter was left to rue more bad defending when Fulham took the lead in the 25th minute.

Hall surrendered possession and Chalobah failed to clear properly before Willian unleashed a powerful drive that took a deflection off Chalobah as it flashed past the wrong-footed Kepa.

Willian didn't celebrate out of respect for his old club but Potter was ashen-faced on the bench as Fulham fans taunted him by singing "Stamford Bridge is falling down" and "you're getting sacked in the morning".

Chelsea were level two minutes after half-time as Mason Mount's free-kick hit the post and rebounded to Koulibaly, who stabbed just over the line before Leno could save.

But even then, Potter's luck wouldn't last as Felix saw red.

Needlessly throwing himself into a high tackle that crashed into Tete's shin, Felix could have no complaints when David Coote flashed the red card.

There was an even more ignomious contribution to Chelsea's downfall from Kepa in the 73rd minute.

Kepa completely misjudged the flight of Pereira's cross, allowing it to sail over his head to Vinicius, who nodded into the empty net while Chelsea defender Thiago Silva screamed at the hapless keeper.