Barcelona manager Xavi said that he is "very hurt" by his side's shock home loss in El Clasico on Wednesday.
The Catalan outfit entered the second leg of their Copa del Rey semi-final with Real Madrid with an advantage, having recorded a 1-0 victory when the two sides locked horns in the first leg at Bernabeu.
However, a stunning performance from the away side saw them run out 4-0 winners to breeze into the final of the competition courtesy of a 4-1 success.
Vinicius Junior levelled the tie in the latter stages of the first period, before Karim Benzema netted a second-half treble for the European and Spanish champions.
Xavi has admitted that a poor second-half performance cost his side in Wednesday night's affair.
"I think that in the first half, we could have finished with a good result. We didn't take advantage of our chances. When you do that against Madrid, it will penalise you. Real Madrid are the favourites in whichever competition they are playing," Xavi told reporters after the match.
"This is a heavy defeat that hurts us a lot. Now we have to be united. I'll have trouble sleeping tonight. I'm very hurt.
"The second half punished us a lot. We competed better than the results suggests. We made very serious errors that showed we did not compete. It's a shame. We have to be self-critical. The second half was very bad.
"I said that Madrid were favourites. We have to congratulate Madrid. They compete very well in cup competitions. It's a shame, but we played against the Champions League winners. I already told you how difficult it was to beat this team.
"This is Madrid. In the first half, they didn't dominate the match, and we created much more but they scored the first goal. We know it. It's how they won the Champions League last year.
"Our moment was in the first half. If we took advantage of the first half the match would have been different. We were run over in the second half.
"I don't think that the players stopped trying, but we got disorganised. It's not an excuse, but I really would have liked to count on the injured players. We have to focus on La Liga now, which is a more important competition than the Copa del Rey."
Barcelona will now be bidding to return to winning ways when they host Girona on Monday evening, with Xavi's team currently boasting an 11-point advantage at the top of the La Liga table. body check tags ::