Wenger tried to remain upbeat despite the disappointing final outcome in Athens.
"We left eight or nine players at home and we had a positive game," he said.
"We had a good first half, but we dropped physically in the second half because many players lack competition at that level and therefore we couldn't take the chances for the second goal.
"We also got a very bad decision against us on the goal. I am not against the fifth referee, but you would like at least for them to be concentrated on their job, but that was not the case tonight, Wojciech Szczesny was far away from the ball.
"Why didn't the fifth official tell the referee? It's difficult to understand, to concede a corner when it doesn't go off the goalkeeper.
"However, I don't want to make a fuss of it, so we have to take it on the chin and go home and focus on our next game."