What's interesting about the matches of these two teams is that both of them met in the Europa League after failing in the UCL.
The two teams met too soon, one between Barcelona and Manchester United will go home.That definitely reduces the excitement level in the Europa League. In terms of performance, I think the two teams are in different situations in each league
I never see manchester united played in UCL before it was playing in Europa league. I guess that if you are wrong about this as menchester united was not playing in champion league for this season. that's also the problem that was triggering ronaldo to leave from the united.
Barcelona was playing at UCL before but it's not for manchester united. Manchester united has been only qualified to play in the europa league. it's not UCL.