Manchester United did not perform badly in the warm-up match against Manchester City, it cannot be said how Manchester United will perform in the Europa League. There is a lot of difference between a warm-up match and a main stage match.
However, we have high expectations for Manchester United in this season of the European League. If this team performs as planned, they have the potential to do well.
Perform well in a single match and perform well through a long season is very different and with latest seasons, we have enough evidence that Manchester United failed to maintain their performances well throughout a long season. They had some great weeks or months but at the end of season, they failed to achieve their target at beginning of season.
Europa League has many matches, not only one match and Manchester United can be affected by their matches in Premier League too. They can not improve and only play like previous seasons, they actually lack of ability to win Europa League even Bayer Leverkusen will no longer be there.
How many goals a team wins against another team is not a big deal but how that team performed consistently. The lack of consistency between Manchester United saw them win one match and lose 5 matches. There are definitely flaws in their plans, Manchester United's defense is a little weak but those of us who understand football fairly well must say their midfield and attacking line-up is very strong yet they cannot do well with this team. If the manager is not able to plan and manage the team properly then the manager should be sacked and a new manager should be appointed because an incompetent manager should never be placed in a competent position.
I will blame the manager directly because Manchester United was not that bad but since the current manager of Manchester United took over the team has started to deteriorate. If the same thing happens from him next season, there is no point in relying on him.