Barcelona manager, Hansi Flick, has claimed his side suffered from fatigue in the 2-1 defeat to Real Madrid on Sunday.
The LaLiga champions tasted defeat for the first time this season.
Madrid took the lead at the Nou Camp after the ball deflected in via Kylian Mbappe.
And although Raphinha equalised for Barca, Mbappe struck again with three minutes left to win the game.
Flick has now said his team was tired, after playing four matches in 12 days.
He said: "We were not playing at the highest level because of the lack of freshness.
"It's not top for us but we have to accept it and defeats is part of the game. It's the first defeat in 10 games.
"We have a whole week before the next game to prepare and disconnect."