The Gunners were in control for most of the match, passing and running with the incisiveness that eluded them against Swansea last weekend. Yet both of their goals came from Mikel Arteta penalty kicks, and both were controversial.
Hardly anyone disagrees that the first should never have been scored. Santi Cazorla shamefully crumpled to the ground when Steven Reid whiffed with a lazy challenge, but referee Mike Jones did not hesitate to point to the spot.
Thereafter, it was Arsenal's game to lose, and they duly took care of business. When Alex Oxlade-Chamberlain went down in the 64th minute, Arteta sealed the game for a Gunners side that was remarkably composed and assured.
Here are six things we learned from their crucial bounce-back win.