Fulham's Harry Wilson scored an 81st-minute winner to condemn 10-man Chelsea to a 2-1 defeat in the Premier League on Wednesday as new Blues head coach Liam Rosenior watched from the stands.
Rosenior will take over a team that dropped to seventh from fifth with the defeat after registering only one win in their last nine games.
The former Strasbourg manager will also need to improve discipline after Marc Cucurella's 22nd-minute red card for hauling down Wilson - Chelsea's eighth of the season in all competitions, including one for former boss Enzo Maresca.
The bustling Wilson proved Chelsea's undoing. He had already had a first-half goal ruled out by VAR for an offside in the buildup and he scored after Chelsea keeper Robert Sanchez had blocked a shot as Fulham piled on the pressure against the tiring visitors.
-- NIGERIA ONLY --
Chelsea had equalised through Liam Delap in the 72nd after Fulham's 55th-minute opener - a diving header from Raul Jimenez.
Chelsea might have squeezed a point from the game but Delap and Moises Caicedo had good chances saved by Bernd Leno in the Fulham goal.
Chelsea's travelling fans made their opposition to the club's American owners clear in chants throughout the defeat.
Maresca departed on New Year's Day after falling out with the owners BlueCo who also run Strasbourg.
It was a difficult loss for interim coach Calum McFarlane against their less prestigious neighbours just 2.2 km across the borough in southwest London.
McFarlane will return to the under-21 team at Chelsea with a draw against Manchester City and Wednesday's defeat to his name.