Arsene Wenger was all smiles ahead of kick off as he celebrated his 1000th game in charge of Arsenal.
His smile quickly disappeared as Chelsea blew his side out of the water in the opening 20 minutes.
Olivier Giroud had the opening opportunity of the game, but his effort was saved after just 3 minutes, and Chelsea went straight down the other end, where Samuel Eto'o curled the ball into the far corner to make it 1-0.
Andre Schurrle then put the Blues two up after seven minutes with a low drive across goal.
Things distended into madness after 17 minutes however, as a penalty was awarded to Chelsea after Oxlade-Chamberlain handled the ball inside his own box. But amazingly, referee Andre Mariner decided to send off Kieran Gibbs instead, despite Oxlade Chamberlain telling the ref it was him who handled the ball.
Hazard converted the penalty, and Oscar added a fourth before half time.
Oscar bagged his second after an hour before Mohammad Salah got his first Chelsea goal to round things off.
