Real Madrid coach Jose Mourinho says Barcelona should focus on football rather than talking about refereeing decisions.
Barca interim coach Jordi Roura has voiced reservations over the appointment of referee Alberto Undiano Mallecano for Tuesday's Copa del Rey second leg between the sides, but Mourinho feels the Catalans need to divert there attention.
"I prefer to stay with the lessons we have received in the past from Barcelona. Lessons in sportsmanship, how to be in football. Not talking about the referees, not surrounding them, trying to get opponents booked," Mourinho told reporters.
"And, of course, giving lessons on how to play football, they do that very well. They would be well advised if they humbly followed that line."
The former Chelsea boss is looking forward to the encounter at Camp Nou as his side look to rescue their season with silverware.
The tie is currently poised at 1-1 following the first leg in Madrid.
"These are the games we like to play and I like going into with the players. We prefer games this dimension and this difficulty," Mourinho said.
Kaka starred in Real's 2-1 victory at Deportivo La Coruna on Saturday, but Mourinho is not sure yet if the Brazilian will make an appearance against the La Liga leaders.
"I do not know. Not that I would not want to say it. I have not thought of it. Normally I do not say it. This time I do not know," he said.
