I think that if Barcelona is able to beat Manchester United it doesn't mean that they will be highly favored as winners of the Europa League trophy because every team that passes to the next round will definitely try hard to achieve their hopes of becoming champions.
Barcelona ever beat MU many times, in the last 3 matches, Barcelona always won. The last won in the Champions league 2019, but in that time, even won, Barcelona is not able to get the champions league trophy because lost versus Liverpool in the semifinal, which mean, MU is not stepped for them to get the trophy, but If Barcelona able to beat them in Eufa league 2022, step for champions is open because MU is one club who can able to stop them on next round, Lewandowski admits it.
The statistic said yeah barcelona is far above MU in any aspect but when we will see the reality and then statistic didn't matter a lot. It's caused by there are many aspects that will be determining the result from the match. Barcelona may be chosen by bookies to be the most favourite team for the next match against MU but i didn't forget if MU has been going back again to the its best form. Lewandowski must also aware if he will face casemiro again. That might be a disaster for him.
The current formation that owned by MU looks perfect from any aspects. Rashford was making MU even scary caused by he was always doing so many contribution to the team.