Nacho Monreal broke the deadlock for the Gunners with just 15 minutes left, giving Wenger's side the advantage in a tight match that looked like it could have gone either way.
Gervinho added another late on to secure the three points, but Wenger believes that the opening goal was the most important one.
"They defended well, as did we. It was a game of defensive stability and we just needed an opening and the first goal was vital," said Wenger.
"We defended high up the pitch and in the whole second half we tried to pin them back, but we did not create many clear chances until the last 20 minutes and once we went 1-0 up I thought more would come."
The win lifts Arsenal back up to fifth in the Premier League table, two points off Chelsea in fourth.