Louis Saha and former Arsenal man Emmanuel Adebayor put the visitors into a two-goal lead after 34 minutes.
But a Bacary Sagna header and a fantastic Robin van Persie strike restored parity before the break, and a second-half brace from Theo Walcott, plus a Tomas Rosicky goal, powered Arsenal to a memorable win.
A last-gasp Ryan Giggs winner - in his 900th Manchester United appearance - secured his club a 2-1 win over Norwich at Carrow Road on Sunday.
Without an ill Wayne Rooney, United made a great start to the match when Paul Scholes nodded home from close range in the eighth minute, but Grant Holt levelled for the hosts in the 83rd minute.
Giggs was there for United when they needed him yet again, with the 38-year-old scoring in the second minute of stoppage to time to trim Manchester City's lead at the top of the English Premier League to just two points.
Stoke City gave their league campaign a much-needed boost on Sunday with a 2-0 win over Swansea at the Britannia Stadium.
Stoke went ahead in the 24th minute via a Matthew Upson header, and Peter Crouch doubled their lead when he powered a header home 15 minutes later.
