The Gunners are now preparing to face Champions League opponents Schalke.
Arteta told arsenal.com: "I have no doubt about the attitude that we have in the dressing room, and the desire. I think the attitude was good [against Manchester United]. We all kept trying, even with 10 men.
"We had a couple of chances to score and we have to give some credit to the lads. But again, conceding those goals against a big team just kills the games."