Real Madrid consigned Barcelona to their fourth straight El Clasico loss with a 2-1 victory thanks to goals from David Alaba and Lucas Vasquez. Sergio Aguero halved the deficit with his first goal for Barcelona.
Barcelona dropped down to ninth on the La Liga table, six points behind leaders Real Sociedad, albeit with a game in hand while Real Madrid are up to second.
"They got it right in the first part and we didn't," Busquets said to Barca TV post-match. "We knew they were going to let us have the ball but they had speed with Rodrigo and Vinicius.
"In a team with these characteristics, when you lose the ball it is difficult to recover. And they have scored a goal in a kick, not in a play. That changes the game completely. I don't think we deserved to lose, but that's football.
"When there are games of these characteristics, the one who scores first has the advantage. In the second half, we had possession and control, but we had not made clear chances."
"Yes, I have seen [the controversial incidents], but it does not matter," Busquets continued. "The referee has been good in general lines and I am not going to respond to the controversies.
"A small gap [in the table] is opening but I think we are growing little by little. Now we are going to recover Ousmane who will give us things in attack. We have to continue."
Barcelona are back in La Liga action at Rayo Vallecano on Wednesday.
