The result saw the North Londoners win 3-1 on the night and 5-1 on aggregate, and Wenger was pleased to see his side respond to criticism from earlier in the campaign.
"It's much better, we needed that to recover from our results," the Frenchman told BT Sport. "It shows how the team has responded. We had a difficult game but in the end we won it.
"It was an open game. We played backwards a bit too much in the first half to protect the result. We played a very good side.
"We have to improve defensively, but overall we are team with technical quality which is more offense-minded.
"We struggle a bit more when we have to defend. We finished the game more compact and more solid."
Victory sees Arsenal reach a European quarter-final for the first time since 2010 and the Gunners will learn their fate in Friday's draw, which begins at 12pm.