If you ask me I can say Manchester United didn't make a mistake against Sevilla and the performance of their coach to give them a good tactic plan in that match was well enough but the reason why they lose this match against Sevilla was the mistakes of some players and especially defenders in Manchester United while unfortunately Harry Maguire is one of them and he is famous for these personal mistakes.
Manchester United failed to qualify for the semifinals due to their own actions. You can see how the mistakes made by their coach in leg 1. Erik Ten Hag failed to maintain the advantage and made the mistake of rotating players at the wrong time so that the rhythm of the game was chaotic and finally Sevilla was able to take advantage of the situation and managed to equalize at 2- 2. In the 2nd leg, Erik Ten Hag was again confused by the number of injured players, so he resigned himself to being defeated by Sevilla again. But what is clear is that MU's failure to qualify for the semifinals was purely due to his own mistakes.