Reference:
if they play Barcelona I expect they will get hammered... probably the same with Madrid.
I don't think they will. Barca play unspeakably crap teams in the Spanish League. Arsenal play 'proper' teams in the PL. They might not win but they won't get hammered unless they bend over and lay out the red carpet for Messi like they did the last time they played them. They literally got out of his way when he was heading towards the goal.
Mourinho has had an ego bashing having got slaughtered by Barca so he will shut up shop completely now and counter attack which makes them very dangerous. I'd rather we play Barca in the later stages than RM, bizarre though that might sound.