LONDON (AP) -- Chelsea handed Arsene Wenger one his most demoralizing defeats as Arsenal manager as his 1,000th game ended in a 6-0 rout on Saturday, and the referee also endured embarrassment at Stamford Bridge.
Chelsea earned its biggest league victory under Jose Mourinho after the leaders raced into a 2-0 lead in just seven minutes through goals from Samuel Eto'o and Andre Schuerrle.
"You come to kill and in 10 minutes we destroyed," Mourinho said. "After that? Easy."
Not for the referee, as Andre Marriner provided the London derby's big talking point by sending off the wrong Arsenal player after 15 minutes.
Although Alex Oxlade-Chamberlain blatantly handled to keep out Eden Hazard's shot, it was Kieran Gibbs who was dismissed despite his teammate's protests. Hazard scored Chelsea's third from the resulting penalty, before Oscar netted twice and Mohamed Salah completed Wenger's misery with his first goal for the leaders.
Arsenal saw its title ambitions seriously dented at it fell seven points behind Chelsea, and faced being dislodged from third place by Manchester City, which hosted Fulham later in the day.
"It's one of the worst days (in my career)," Wenger told the BBC. "It's over after 20 minutes and it's a long game after that."
After the humiliation Wenger did not attend the mandatory post-match media conference, with Arsenal media chief Mark Gonnella saying the team bus had to leave while Mourinho was addressing reporters.
The Frenchman couldn't get away quick enough after another gloomy landmark day at Stamford Bridge. His 500th game in charge also saw Arsenal lose at Chelsea, albeit only 1-0 in 2005.
The margin of this defeat matched the previous low-point of Wenger's 18-year reign -- an 8-2 loss at Manchester United. It was also Arsenal's third big away loss against its direct title rivals this season, following a 6-3 defeat at Manchester City and 5-1 drubbing at Liverpool.
And the humbling only served to justify Mourinho's recent gibe that Wenger is a "specialist in failure" as the Frenchman went an 11th game without beating his Portuguese rival.
"Two-nil after seven minutes and the game is over, because we were too strong for them," Mourinho said.
Chelsea took control of the game from a counterattack straight after goalkeeper Petr Cech had denied Olivier Giroud.
Schuerrle ran through the center from the halfway line and passed to Eto'o on the edge of the penalty area, and the Cameroon striker controlled the ball before curling it past the diving Wojciech Szczesny in the fifth minute.
In a near replica move, Arsenal's defense crumbled again inside two minutes as the provider turned scorer. Nemanja Matic seized possession around the halfway line and fed Schuerrle, who went past Laurent Koscielny before scoring.
Although Eto'o was forced off injured in the 10th minute -- and replaced by Fernando Torres -- he had already provided a key contribution for Chelsea.
"Arsene Wenger, we want you to stay," Chelsea fans taunted.
It was to get a lot worse for Wenger's side -- and the referee -- when Hazard's shot was tipped away, not by Szczesny, but by Oxlade-Chamberlain.
Despite the clearest of diving saves by an outfield player, Marriner somehow managed to identify Gibbs as the offender despite Oxlade-Chamberlain being seen admitting to the referee: "It was me."
"I believe it was handball but the referee hasn't seen it," Wenger said. "The ball went out and I think it's Chamberlain who touched the ball.
"I don't know who gave indication to the referee that it was handball but he has certainly not seen it."
Hazard scored from the penalty spot and there was no way back for Arsenal.
Just before halftime, Schuerrle released Torres, who squared into the center for Oscar to scoop in from close range. Oscar's second in the 66th was in part down to a goalkeeping blunder as Szczesny allowed his curling shot from outside the area to slip through his hands.
And Szczesny allowed Salah's shot to roll under him four minutes later to cap an all-around dismal performance by the visitors.
"This defeat is my fault, I take full responsibility for it," Wenger said. "I don't think there's too much need to talk about the mistakes we made. We got a good hiding today."
Rob Harris can be followed at www.twitter.com/RobHarris