The 25-year-old was recalled to the starting XI to give leading forward Olivier Giroud a rest, and headed the hosts in front inside two minutes.
"Look, [it is a gamble] if a guy has not played for a long time, and his last performance was not convincing against Chelsea, but he has worked hard in training and deserved a chance," said Wenger.
"We know that when he has the mind on the game, he has the qualities. I believe tonight he had a good game.
"He has the stature, he has good technical quality, he has quite good pace.
"We had him as a boy of 15 or 16 and I made him sign a long contract twice, so that means I always believed in his qualities."
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