Arsenal Cazorla Giroud
Arsenal players Santi Cazorla and Olivier Giroud react after the ball strikes the crossbar in the Champions League game against Borussia Dortmund, October 22Reuters

Arsenal manager Arsene Wenger was noncommittal about the possible sending off incident of Roberto Lewandowski, who eventually turned out to be the matchwinner for Dortmund in their Champions League game at the Emirates.

The Gunners suffered their first defeat in Europe this season on Tuesday night, going down 2-1 to last year's runners-up in a high-octane, yet a little bit disappointing, clash at the Emirates.

Henrikh Mkhitaryan opened the scoring for Dortmund in the 16th minute, before Olivier Giroud equalised just before halftime. However, Dortmund would have the final say, with Lewandowski finishing off a quick counter-attack late in the second half.

Apart from the goals, the main talking point of the night, though, was when Lewandowski seemed to plant a cynical elbow into Laurent Koscielny's face midway through the second half. The referee seemed to see the incident directly and gave the Polish striker a yellow card, although replays suggested maybe it should have been the red variety.

"It looked like (it could have been a red card) but I haven't seen it well, but the referee was in a much better position than I was and didn't decide to do it," Wenger said. "I will have to look at it again, I don't know."

After the unbelievable highs of Napoli, Arsenal were much more underwhelming against Dortmund, with the attacking side of the English Premier League side rarely coming to the fore.

"It was a game of high intensity but very few chances," said Wenger, whose side went extremely close a couple of times to making it 2-1 said. "Dortmund were well organised to stop us from playing, and I must says as well that we were not as good as we can be offensively.

"Some of our players were not as fresh as they were recently. But we put ourselves on the back foot with the first goal and naive for the second goal. If you look at the number of saves our keeper had to make tonight and you concede two goals, you can say that we can only look at ourselves for not being mature enough in situations like that.

"If you cannot win the game, you don't lose it. Especially in the second half when we were on top, we made things difficult for ourselves by giving them the second goal."

Jack Wilshere was one of several players who had off days, with the midfielder picking up a knock on his Achilles early in the game, which probably restricted his effectiveness.

"You could see that he was not completely himself and that is why I decided to take him off," Wenger, who brought on Santi Cazorla in Wilshere's place early in the first half, said. "At the moment it is his desire to play that gets him through the game.

"It looks like he was handicapped after the first tackle he got. He looked like he landed awkwardly. He looked to me that he limped a little bit. We will see how he responds in the next two or three days, we haves to wait for the medical assessment."

The win for the German side makes Group F extremely tight with Arsenal, Dortmund and Napoli, who beat Marseille on Tuesday, all on six points after three matches.