Theo Walcott and Olivier Giroud gave the Gunners a 2-0 lead in the Group B clash in the Veltins Arena but Klaas Jan Huntelaar pulled a goal back before the interval and Jefferson Farfan's second-half goal earned the German side a point.
Arteta told Sky Sports 2: "Considering we were 2-0 up, it can't be good for us. We had the last chance too with Theo.
"We were unlucky to concede just before half-time. It was a completely different game, but that happened.
"But this is not an easy place to come. We'll take the point."
Walcott echoed those sentiments and said: "It was a good point in the end. It would have been a fantastic victory, they dominated the second half but we defended quite strongly.
"We'll try to win our last couple of games and as long as we do that, we'll get into the next round."