The only goal scored in the game came from a corner kick that Calafiori perfectly capitalized on, so it would be absurd to attribute the defeat to mistakes or defensive fragility. Man United attacking line should be the one that needs correction, players like Bryan Mbeumo, Matheus Cunha, and Benjamin Sesko have not been able to capitalize on golden opportunities due to a lack of coordination and good finishing. They had 17 shots, only 5 of which were on target, none of which managed to enter Arsenal goal.
This result is not too disappointing considering that Arsenal is not a weak team, conceding one goal is very normal in a big match game against opponents whose strength is almost equal. Amorim needs to sharpen their attacking line in the next match because based on the results in the first match, their weak point lies in their inability to break down Arsenal defense.
Even from the replays been shown, it wasn't even a mistake from the part of Manchester United, it wasn't a goalkeeper error. It's just that that Arsenal defender was smart enough to disrupt the goalkeeper, that would have been an infringement on the goalkeeper and I wonder why the ref didn't cancel the goal even after his seen the replay. Although, Manchester United players were not clinical enough if not, they would have drawn or even won the match.