Goals from Theo Walcott, Aaron Ramsey and Olivier Giroud put Arsene Wenger's side 3-0 ahead before Alvaro Negredo replied late on for City.
And the result was reward for Arsenal's greater efficiency in front of goal, their three strikes coming from just four shots on target.
Walcott opened the scoring nine minutes in, coming in off the right to control Aaron Ramsey's lovely pass and poke a finish over Joe Hart.
Hart tipped Bacary Sagna's long-range shot against a post, while at the other end Wojciech Szczesny denied Edin Dzeko and Negredo caused the Arsenal defenders plenty of problems.
But two goals in four minutes after half-time put the Londoners out of sight, Walcott sliding in Ramsey for the second (59) and substitute Giroud lobbing Hart with the keeper in no man's land (62).
Colombian trialist Sebastian Perez came on for Arsenal, his most notable contribution a foul on David Silva which brought a booking.
And Negredo got the goal his personal performance merited with 11 minutes left, City's summer signing holding off Laurent Koscielny and firing under Lukasz Fabianski.