Wenger was serving the touchline ban landed for his sending off against Sevilla last month, but refused to explain how he communicated during the match.
He said: "We had a good first half and overall our game was well organised. Our combination play was good.
"We were not clinical enough to finish what we created but overall I was happy.
"In the second half our game dropped and from what I could see from upstairs that was for physical reasons.
"The main reason for that was we had players like Robin van Persie, Diaby and Alexandre Song back from injury."
Van Persie made his first appearance since October 7 after recovering from a knee injury and Wenger is ready to play him in Sunday's Barclays Premier League clash with Chelsea.
He said: "The game was no problem for Van Persie. He looked sharp - his eye was there and his pass was there.
"He needs to grow in confidence for his tackling but on the footballing side it looked like he'd never been out. He's ready for Chelsea."