He said: "It was tough, they made it really tough for us and defended really well. We hit it off not bad, but then looked nervous. The result from the weekend drained us a little, we lost a little bit of confidence, but overall it is a fantastic result.
"We will have a look and try to correct [some things]. Overall they did not have a lot of chances but they played well. They're a good side, technically sound and made it hard for us. We watched tapes and knew they had good technique.
"The other game [in the group] was a draw but it's early days, we've still got an awful lot of work to do."
Arsenal are top of Group B with 100% record after two matches, and face second-placed Schalke in their next European match on Wednesday, October 24.