UCL is just another excuse by Arteta. When you compare his club to the Liverpool, it's totally different. His club is still far away from winning UCL, meanwhile Liverpool is a few steps closer to PL title. He's also walked out after the journalist asked him about PL title challenge against Liverpool.
That's why he said that to avoid being blamed or mocked by his rival. The better you wait until his club leave from UCL, then see what's gonna happen with him.
He doesn't really has anything to offer the club at this point and I think he is not having anything to say to the journalist, if they really are that confident in there place about the place and winning the Champions League, he will says nice things and wouldn't walk out but we have to see what they can do because been a second place in the Premier League with many point difference is really not enough but some people are using the goals scored to judge.
Somebody said what if Arsenal show us the biggest surprise in the history of football and makes Arsenal to win Real Madrid in their next match, I responded immediately that they can't and he was laughing that I was underrating their clubs but that's just the truth. PSV was just another unfortunate team that was trying to win the Champions League, they don't deserve to be here but Arsenal made it quick my reminder removing them and they think they are the chosen.