The Gunners scored three goals within 20 minutes into the first half to record their biggest ever premier league win against rival Manchester United since 1998 at High bury.
Coming from the back of a 3-2 home loss to Olympiakos in midweek, Arsenal quartet of Alexis Sanchez, Theo Walcot and Mesut Ozil produced a clinical performance to tear apart Manchester United with a 3-0 win.
Arsenal was up for a statement with Alexis Sanchez and Mesut Ozil stucking two goals to put the Gunners 2-0 ahead within a mere six minutes of play.
The Chilean tore a part the Red Devils defense before ramming home his fifth goal of the season in the 20th minute.
Manchester United dominated possession in the second half but failed to convert their chances with Petr Cech being in his best to deny Anthony Martial a goal from a close range.
The win moves Arsenal to position two behind the league leaders Manchester City.