Chelsea suffered their first defeat to Fulham since 2006, in another dismal display from Graham Potter's side, which now leaves them four places behind their West London rivals in the Premier League table.
Here's what we learnt from last night's fixture:
Ciao Felix -
Much of the pre-game focus had been directed at new Chelsea signing Joao Felix,, but the Portuguese forward had a debut to forget as he received a straight red card in the second half due to a high, lunging tackle which saw both of his feet leave the floor.
Though he had been bright in the first half, forcing saves from Fulham goalkeeper Bernd Leno and providing good link up play with his new teammates, his reckless challenge undid the work his side had done to get back into the game through Kalidou Koulibaly's equalising goal.
Felix, who joined from Atletico Madrid on a six month loan deal, is now suspended for Chelsea's next three league fixtures against Crystal Palace, Liverpool and the return fixture against Fulham.
Chelsea were unable to hold on with ten men, painting Felix as the evening's villain. He became the first Chelsea player to be sent off on their Premier League debut and the first to do so for any club since October 2014, when Federico Fazio received a red card for Tottenham Hotspur.
Fulham Flying -
Fulham's fourth consecutive win leaves them sitting sixth and in the European qualification places. These dizzy heights are fairly unfamiliar for the Craven Cottage team, but this season they have secured a 47% win ratio and are exceeding expectations.
Their home form has proved a particular strength and has seen them win half of the matches that they have played at their Thames riverside stadium.
Their next match takes them to St James' Park to take on a Newcastle United who are enjoying an unexpected elevated position in the table.
Chelsea old boy Willian, who spent seven years at Stamford Bridge, punished his former side to open the scoring, showing the kind of energy and drive that made him so popular with the club's supporters. He respectfully held up his hands to acknowledge his time at the club instead of celebrating his goal, and the away fans continued to sing his name until his substitution in the second half.
Even without suspended talisman Aleksander Mitrovic, Fulham managed to make their nearest neighbours look mediocre, with stand in striker Carlos Vinicius bagging the winning goal.
Stuttering Start -
Potter's Chelsea are still winless in 2023 and are out of both domestic cup competitions. Sitting in tenth place in the Premier League, it has undoubtedly been a dismal start to the new year. His side have now lost eight games this season and sit 12th in terms of goals scored.
The wait for the treatment table is more in demand than starting positions available in his team at the moment, with an injury to another loanee, Denis Zakaria, adding to Potter's injury woes, which have been colossal.
Although he threw almost every substitute named on the bench into the action, his Chelsea team continue to look disorganised and depleted, lacking any cutting edge or fire power. Felix did provide some of that much needed spark in his first half performance, but his sending off ensured that the evening was another case of one step forward and two steps back for the blues.
Boehly Believes -
One thing is for sure, Chelsea really have changed tact with new owner Todd Boehly. You don't have to follow football to know that Chelsea have been renowned for chopping and changing their manager at the first sign of trouble over the last two decades.
Were Roman Abramovich still at the helm, news would surely already have reached us about Potter's dismissal. But, Boehly has a different plan and seems to be sticking with his under pressure manager.
It does appear that little could be improved with an instant change of personnel, with little left to play for and stiff competition for European qualification, if that is still believed to be in reach.
A second change this season does not appear to be on the cards. Potter will likely be given more time and leniency than has previously been afforded to his predecessors, but he can no longer be under any illusions about the difficulty of the task at hand.