And in the return games we beat those teams 3-0. Other than overestimating ourselves or underestimating the opposition there is really no reason why we shouldn't get in the latter stages of the Europa League/win it. We usually get results against the level of teams we'll face in the Europa League.
We would be the biggest club in the competition by reputation and by resources. Plus all the other reasons I gave, there is no reason not to go 100% for the Europa League. When we do that, we should be able to win it.
It's the biggest opportunity for Wenger to deliver some decent silverware after the 15/16 League title. I'm sceptical, but let's see how he's going to handle it.