Barcelona defender Jules Kounde admits they struggled to live with Manchester United after halftime of their Europa League defeat.
Barca were 1-0 ahead before United stormed back to win 2-1 and progress 4-3 on aggregate.
Kounde said, "It's painful to be knocked out like this. We played a very good first half but we conceded far too early in the second half.
"Once the game went to 1-1 we lost the control we'd established. That's very disappointing. But I think we need to give credit to our rival too. They went up a gear in the second half and made it very tough for us.
"I'm sorry for our loyal, noisy fans who were here tonight.
"Like them, our objective was to win the Europa League. This and the Champions League group need to be learned from We have to go up a level and I'm confident that we'll do that next season. We are a young squad and we'll just need to keep improving."