Barcelona manager Hansi Flick called on his players to refrain from "disrespectful" behaviour toward match officials after Real Madrid's Jude Bellingham was shown a straight red card for arguing with the referee in their 1-1 draw at Osasuna.
Bellingham said after Saturday's game he had not insulted the referee and described the situation as a misunderstanding. On Sunday he apologised on social media for "leaving my teammates in such a tough position".
Flick, speaking ahead of Barcelona's home game against Rayo Vallecano on Monday, said he had reminded his squad of the importance of avoiding confrontations with match officials.
"It's disrespect. For me, it's like that. But I don't have to decide (the punishments)," he told a press conference on Sunday.
"I don't like this behaviour and I said this today to my players because it's very important. It is not good for the team when you do this and get the red card. It's a weakness and we don't like that.
"We have one person on the pitch who is allowed to discuss with the referee and that is the captain. We have to accept that."
Third-placed Barca can return to the top of LaLiga with a win over Rayo later on Monday.