I know about level and different competitive between Primer League and La Liga but can't be comparison thing, several time La Liga team success dominance than Primer League teams not only in Europe League but also in Champion League. Have difference atmosphere with Europe League competition and all teams want to get great achievement.
Who is to say you do not know about this? Did I discuss with you before on this one? Because yesterday I discussed this with @Rabi3 and I did not mention anyone about whether or not they know the level of the Premier League and La Liga. But this is actually not a problem because anyone can discuss it here even though with a slightly different tone. Ok this is Europa League and I was talking about Europa League with @Rabi3 and we didn't talk about Champions League because everyone knows how level Champions League is. So I'm not going to talk about the Champions League but only for the Europa League.
As I recall, Barcelona also failed in the Europa League last season, even though the chances are almost the same as this season and I think you know who won the Europa League title last season. If Barcelona is strong enough this season Barcelona should not be in the Europa League but in a competition that is greater than the Europa League.
I don't sure with Primer League higher level than La Liga will make Barcelona loss compete against Manchester United at playoff round, seem Barcelona more favorite lead to next round than Manchester United based on domestic league achievement by both teams.
In the Premier League this season Arsenal have looked very consistent in winning matches and I don't think you have missed the Manchester United vs Arsenal match which took place three days ago either. It was clear that they played fiercely by scoring goals in the first half and also in the second half even though Arsenal benefited greatly from that match because Nketiah was able to score again in the 90th minute.
This means that Manchester United this season is better than last season so when they meet Barcelona in the Europa League, I think the match will also be more exciting and fierce because the strengths are almost the same and the chances of winning the game are not much different for the two.