Spain coach Vicente del Bosque is concerned that the current run of Barcelona-Real Madrid matches could have a negative effect on the national team.
Tensions were high going into Wednesday's first leg of the Champions League semifinals between the two clubs. It was the third of four meetings in a short span between the rivals, with several Spain teammates having squared up to each other during Madrid's 1-0 Copa del Rey extra-time final victory last week.
"I'm worried about the quarrels between my players during these clasicos, which I hope don't find their way into my locker room," Del Bosque is quoted as saying in Wednesday's Marca newspaper. "Good relations inside the locker room are the basis for our future success."
Jose Mourinho and Pep Guardiola also engaged in a verbal sparring match on Tuesday when Barcelona coach Guardiola let fly an expletive-laden retort in response to his Portuguese counterparts taunts from earlier in the day.
Villarreal defender Carlos Marchena called on his Spain teammates to remember the big picture amid the marathon of clasicos, which started with a 1-1 league draw on April 16 and will close with Tuesday's Champions League return leg.
"You have to be intelligent and remember that the national team lies above any club ties," Marchena said.