Manchester United boss Erik ten Hag branded their performance "unacceptable" after being thoroughly beaten 3-0 by Sevilla on Thursday night.
Youssef En-Nesyri struck twice and Loic Bade also scored as Sevilla reached the Europa League semifinals 5-2 on aggregate.
"This was a great opportunity, a great occasion, to win something and we gave it away - we have to blame ourselves," said Ten Hag.
"It's gone, we can't change it. We have to look forward to Sunday, that's the next opportunity.
"It's unacceptable. We lost the battles, they had more passion, more desire, more willingness, that's difficult to win games.
"We can't run away from it. On Sunday we have another opportunity and have to step up and show more character and personality."
