"I enjoyed every minute of it," said Wenger. "It was a big test for such a young team.
"Many players were under 18 and we stood up to the test and got a remarkable combination of desire, energy and quality.
"From the first to the last minute we looked really up for it. We had a relentless go. In the end it was a fantastic win.
"These boys, they surprise everybody because there is a mixture of character, commitment and calm as well. Under pressure they remain extremely calm and play always very good football.
"What they do on the pitch is not a coincidence, it is quality.
"I will keep them together to see how far they can go. First we had Sheffield United and then Wigan.
"They were different challenges but now you know they can turn up and produce. It is interesting to go into the quarter-final and to see who we get.
"Simpson had a great pre-season but we have great competition in the strikers with Carlos Vela, Nicklas Bendtner, Robin van Persie and Emmanuel Adebayor, but he has shown again tonight his character and that he is physically strong.
"He has shown he is a good player. He was player of the year last year when he was on loan with Millwall last season."