Lucas Perez opened scoring for the visiting side in the 16th minute and doubled the goal few minutes before the end of the first half.
He scored his third at the 47th minute to make the home side’s hope of a comeback more difficult.
At the 53rd minute, Alex Iwobi caped the haul of goals for the Gunners before Seydou Doumbia got a consolation goal for the home side.
In the other Group A games French money bags, Paris Saint Germain, played a 2-2 draw with Bulgarian side Ludogorets Razgraad to relinquish top spot to the Gunners
Elsewhere, Italian side Napoli beat Benfica 2-1 away while Ukrainian side Dynamo Kiev went goal crazy putting six goals past Besiktas.
Catalan giants, Barcelona, also beat Borrussia Moenchegladbach 4-0.
Super Eagles forward, Kelechi Iheanacho, scored for Manchester City against Celtic but the Scottish side held on for a 1-1 draw at the Etihad Stadium.
Bayern Munich got their pound of flesh against Atletico with a 1-nil victory in Munich while PSV Eindhoven and FC Rostov played a goalless draw.