A 95th-minute strike from Rodrigo Muniz saw the Blues lose at Stamford Bridge as they failed to close the gap on Liverpool.
Chelsea dropped more points in the Premier League title race after conceding in the final minute of a 2-1 loss to rivals Fulham on Boxing Day.
Enzo Maresca's Blues have now failed to win in back to back matches against sides from outside the traditional 'big six' and now sit four points behind leaders Liverpool, who boast two games in hand.
Marco Silva set his side up with a back-five formation in the hope of spoiling the hosts' Christmas, but those prayers were quickly rejected when Chelsea took the lead inside 16 minutes through none other than Cole Palmer. Picking up possession midway inside the Fulham half, he weaved his way past two hapless defenders before curling in a strike at the near post from the edge of the box, with the ball rolling between the legs of centre-back Issa Diop on the way in for good measure.
Fulham went close to an equaliser soon after when Calvin Bassey burst forward from the centre of defence and all the way into the Chelsea box on a run that mimicked that of a tricky winger. He quickly remembered his actual position with a limp finish which was easily saved by Robert Sanchez.
Down the other end, Chelsea ought to have doubled their lead. Enzo Fernandez's delivery from a wide free-kick picked out Marc Cucurella, whose close-range header was tipped away by Bernd Leno and the visitors were able to clear their lines just in time.
On the other side of the interval, Fernandez brought a great save out of Leno himself with a top corner-bound strike from 20 yards, only for the German to claw his effort up and out. Chelsea had the ball in the net from the second delivery of the resulting corner when Palmer's cross was bundled in by Levi Colwill, only for the offside flag to deny them on this occasion.
Fulham grew into the game in the second half and the Blues had Sanchez to thank for staying ahead after he smothered Antonee Robinson's attempt when the USMNT star was given the freedom of the six-yard box.
With little under 10 minutes remaining, Fulham had their leveller. Alex Iwobi forced his way past Pedro Neto and slipped in Robinson, whose cross was knocked back by Timothy Castagne and in for Harry Wilson to prod over the line.
Chelsea quickly rallied to try and find a late winner but were denied by a top stop from Leno when the ball fell to Sancho inside the 18-yard box. With Maresca pushing everyone forward, Fulham hit the Blues on the break for a last-gasp goal of their own. Sasa Lukic broke down the right and found Rodrigo Muniz steaming in to slam home and send the travelling fans crazy.
GOAL rates Chelsea's players from Stamford Bridge…
Getty Images SportGoalkeeper & Defence
Robert Sanchez (7/10):
Saved Chelsea's skin on a few occasions with some fine stops. Was also quick off his line to claim a few teasing crosses. Let down by the defence in front of him.
Malo Gusto (5/10):
Bombed on down the wing and into midfield but to little gain for his side, often used as a dummy runner rather than getting on the ball himself.
Tosin Adarabioyo (6/10):
Booed throughout by the away end after leaving on a free transfer at the end of his contract in June. Didn't let that faze him, at least.
Levi Colwill (5/10):
Drifted across to help Cucurella defend against Traore, who provided one hell of a physical battle for both. Surprisingly, it was the centre-back who struggled a bit more in this department.
Marc Cucurella (6/10):
Never let compatriot Traore outwork him, even if the Fulham winger was easily the quicker player. His energy proved infectious around Stamford Bridge. Caught high up the pitch for Muniz's dagger with Chelsea trying to find a winner themselves.
AdvertisementGetty Images SportMidfield
Moises Caicedo (5/10):
A tale of two performances from Chelsea's deepest midfielders. Caicedo, though industrious and a leader by example off the ball, found himself unable to open the game up with a series of unsuccessful long passes frustrating the home side.
Enzo Fernandez (5/10):
Captain Fernandez, meanwhile, showed all the quality of a top-level central midfielder on the ball, only for his display to be undermined by some strange and ill-advised challenges when trying to win it back, with Fulham exploiting the space he would tend to leave with his over-enthusiasm.
Cole Palmer (7/10):
Palmer marked his final home game of the year in style, with his deadlock-breaker one to watch on repeat for years to come. Broke Jimmy Floyd Hasselbaink's record for Premier League goals for Chelsea in a calendar year, taking his tally to 26 in 2024.
Getty Images SportAttack
Pedro Neto (4/10):
Spent a lot of time in his own half covering for Gusto. When Neto did find himself in attacking areas, he'd leave you wanting more after beating one man but never two or three. Went down too easily in his duel with Iwobi leading to Wilson's equaliser.
Nicolas Jackson (5/10):
A selfless display from Chelsea's busy centre forward, running the channels though seldom creating opportunities of his own. Brought off for Nkunku for the finall 20 minutes or so.
Jadon Sancho (6/10):
Extremely bright when isolating himself with wing-back Castagne. Didn't get involved a whole deal aside from those instances, however.
Getty Images SportSubs & Manager
Christopher Nkunku (5/10):
Replaced Jackson for the last act of the afternoon. Didn't provide the same sort of focal point.
Enzo Maresca (5/10):
Chelsea fans surrounding the press box vehemently questioned why the Blues boss used only one sub. His side were outplayed by their local rivals and he did little to stem that tide.