Barcelona defender Jules Kounde admits they failed to handle Real Madrid's counterattacks for Sunday's 3-1 defeat.
Kounde said Barça should have made fouls in the build-up to goals from Karim Benzema and Fede Valverde, which handed Madrid a two-goal lead at the break.
"Really disappointed," Kounde said to DAZN.
"We have not played poorly, but in the first half we slipped up where they are strong, in the transitions.
"We should have made the foul to avoid the first goal and the second is the same. That's the strength of Madrid. Two chances, two goals. We have to learn that."