Alexandre Lacazette and Aaron Ramsey scored two goals each as the Gunners hit four in 26 minutes before half-time.
Arsenal were unable to add to their tally in the second half but they will head to Russia's capital for the second leg next Thursday with a commanding lead.
It was the dream return from injury for Lacazette, who duly helped his side all but confirm their place in the Europa League semi-finals as Arsenal's quest for Champions League qualification intensifies.
Here are five things RealSport learned from the game: