In terms of experience, it is possible that Arsenal players do not have enough experience in the Champions League because you can see that arsenal players are dominated by young players and they have just returned to the Champions League after being absent in the previous season. I think Arteta must be able to raise the enthusiasm of his players in the upcoming match against Sevilla because arsenal must try well in order to qualify for the next round.
A defeat in the champions league at the stage where it will not cost them the competition is okay to remind them that this is a different environment from the English premier league and the teams they are playing even though they are not rated much in their various league will be focused to go as far as they can in this competition. Arsenal will take their game against Sevilla more seriously and since they have some key players back, they still are very well in a good position to win Sevilla and send them to the Europa which is the competition they are known for.