Barca have suffered consecutive El Clasico defeats, along with a loss to AC Milan in the Champions League in the past fortnight.
"We were a little better today than we were at the Camp Nou, but we have to give a lot more of ourselves," he said.
"We weren't fluid like we usually are and we're missing certain things. We've had these bad moments when we won a lot of titles, but we have to end this poor streak as soon as possible ... I don't think it's the right moment to criticize our style of play, we've secured a lot of good results with it."