A second half shambles resulted in a week of agony ending in shameful scenes on the pitch as Everton dumped Chelsea out of the FA Cup.
Diego Costa was sent off for the first time in his Chelsea career when he saw red for retaliating on a Gareth Barry challenge.
He had already being given a yellow card. But, with the Londoners already 2-0 down thanks to an explosive spell by Romelu Lukaku, he decided to square up to Barry, head butt him and then appear to bite the neck of the midfielder.
It was an unprofessional response to a performance that saw the champions dumped out of the Champions League in midweek and the FA Cup within four days.
Chelsea season has descended to chaos.
This was a game Guus Hiddink set his team up night lose, but it ended controversy that could see Costa banned for 10 matches or more, ending his season.
This could have been the last time he wore the Blue of Chelsea as Roman Abramovich should sack the striker or at least sell him to the lowest bidder.
Everton started like bats out of hell, forcing Thibaut Courtois into a save in the first minute. But Chelsea responded well with make-shift left-back Kenedy blasting over from eight yards out. Had he being calmer, he could have realised he had time to take the ball down and control it.
A flashpoint occurred on nine minutes when Costa responded to a smash by Gareth Barry to returning the favour. Referee Michael Oliver brandished a yellow card to the put-upon hit man.
Everton's abrasive game did for Pedro on 16 minutes when Shamus Coleman up ended the Spain wide man.
Costa went down in the penalty area, on 20 minutes, demanding a spot kick after he felt he was bundled over by Phil Jagielka. But Oliver just waved the desperate plea away.
The England man was given a yellow three minutes from the break after cluttering Cesc Fabregas.
Willian took the 25-yard free kick which arrowed towards goal,mug Joel Robles confidently tipped the ball over his crossbar foe a corner.
Everton's second effort on goal was a minute later, following a count-attack which saw Tom Cleverly try a clever left-footer from the edge of Chelsea area, but Courtois, dived to his left to keep warm, and stop the ball.
There were no changes of personnel at halftime, Ramiro Funes Mori had the first chance of the second period, but he headed over f rom a corner.
Costa really should have scored on 58 minutes when he slide through the home side's defence, latching onto a Fabregas through ball but the angle was tight and the ball rolled across the goal line, inches away from a tap-in, if only a Chelsea play was alive to the situation.
With 13 minutes on the clock, Lukaku weaved his way through Ivanovic, Azpilicueta, Mikel, before twisting Cahill in two and planting the ball wide of Courtois and Into the back of the net to send the home fans delirious.
Guus Hiddink replaced left back Kenedy for Loic Remy but disaster struck immediately as Lukaku raced clear from that very same position, and he smashed the ball home past Coutois.
Incredibly Chelsea's discipline dissolved a minute later when Gareth Barry and Costa locked horns with the Spain striker appearing to head butt Barry with a possibility of a small bite to the neck.
Oliver gave a second yellow then red to the forward. Barry was sent off too.
It was a chaotic and shambolic end to the match.
Chelsea have nothing left to play for his season.
Teams: Chelsea, Courtois; Azpilicueta, Cahill, Ivanovic (c), Kenedy; Mikel, Matic; Willian, Fabregas, Pedro; Diego Costa.
Subs - Begovic, Rahman, Terry, Loftus-Cheek, Oscar, Traore, Remy
Everton, Robles, , Coleman, Jagielka, Funes Mori, Baines, McCarthey, Barkley, Cleverley, Lukaku
Subs, Stones, Kone, Niasse, Besic, Delofeu, Osman, Howard
Referee, Michael Oliver