I can only speak for myself, but against every team other than the top 6 and Stoke away I am of the opinion that Arsenal should beat them. That they choose not too do that is a whole other discussion.
I just assume Arsenall will also use a different approach in these games and have a different mindset because the games are two-legged in stead of it being just another League game.
Except for Dortmund, Zenit, Napoli and Atletico we are talking about teams who aren’t exactly top bracket in their respective Leagues. Sure Arsenal isn’t either, but it’s still Arsenal, and our floor on a bad day is very low but we should be confident against the likes of Bilbao, CSKA, Sociedad, Sporting CP etc.