Barcelona are not affected by off-field matters amid the ongoing Negreira scandal, head coach Xavi said.

The Catalan giants are subject to an investigation from UEFA with prosecutors in Spain pursuing charges for alleged corruption, having allegedly paid over $7.6 million to the company owned by former vice-president of the refereeing committee in Spain, Jose Maria Enriquez Negreira.

LaLiga cannot take action due to a statute of limitations in Spain but, speaking on Monday, UEFA president Aleksander Ceferin confirmed no such restrictions are in place for their investigation, while talking up the severity of the scandal.

Barcelona have denied any wrongdoing.

And Xavi insists the allegations are having no impact on his squad.

"Extra-sporting issues don't go into the locker room. We talk about how to defend, how to attack. We are not talking about UEFA, nor Negreira," he told a press conference ahead of the Copa del Rey semi-final second leg against Real Madrid.

"We are focused on the Cup: there is a Clasico, they will come wanting revenge and we want to show that we can win again. The Camp Nou has to be a pressure cooker.

"I listen very little [to outside comments] and we value from within. The president values it very much. If the boss is not happy, it matters what is said from outside.

"Nothing should divert us, tomorrow we can have a double joy: to beat Madrid and reach a final. We are much better than last season."

On Monday, Barcelona issued a statement urging LaLiga president Javier Tebas to resign after alleged false claims in the Negreira case but Xavi refused to comment on the matter.

"I don't know him, we have greeted each other two three times, and I don't have a clear opinion," he added.

Barcelona hold a slender 1-0 advantage heading into Wednesday's game. However, Madrid are still the favorite, Xavi believes, saying: "When we have a two-legged game, I have the feeling that it is very difficult. How long has it been since they lost a two-legged tie?"

"That's why for me they are still the favorites despite the 0-1. They have more pressure than we do.

"Madrid can beat you perfectly. For me it is very even and they have a point that makes them favorites, they are used to coming back from matches."