The Ivorian was sent off for a headbutt in last weekend’s Premier League clash at Elland Road, but kept his place in the side for the trip to Norway and opened the scoring with a superb finish.
Arsenal, disappointing in a drab first half against the Norwegian side they beat 4-1 at home, doubled their lead five minutes later when Reiss Nelson converted a precise low cross.
The double setback knocked the stuffing out of Molde and Arsenal threatened to extend their advantage with Alexander Lacazette denied by home keeper Andreas Linde.
Substitute Folarin Balogun, 19, made it 3-0 to the visitors with his first goal for the club, moments after coming on to silence the few home fans that were allowed inside the stadium.
Arsenal's win left them top of Group B with a maximum 12 points from four games, six clear of Molde.
Rapid Vienna, who have three points, face Dundalk later.
Additional reporting by Reuters.
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