Real Madrid forward Denis Cheryshev insists he was not notified that he was banned for his side's 3-1 Copa del Rey win over Cadiz on Wednesday.

The Russia international started and scored in Madrid's victory, but should not have been on the field because of a one-match suspension for receiving three yellow cards in the competition while on loan at Villarreal last season.

"I did not receive any notification from Villarreal to inform me that I had been banned from playing in the Copa del Rey," Cheryshev told Madrid's official website.

Fielding the ineligible Cheryshev could see Madrid kicked out of the Copa, with Osasuna eliminated from the competition for a similar offence earlier this year.

Nevertheless, Madrid's director of institutional relations, Emilio Butragueno, is hopeful the Santiago Bernabeu side might escape such punishment because Cheryshev did not receive notification.

"The club were not notified about the sanction. We did not receive any form of notification from the federation or from Villarreal and nor was the player informed about the circumstances," Butragueno told reporters.

"This is not about looking for someone to take the blame. We are going to wait and see what happens. There is an article 41 of the Spanish Football Federation's Disciplinary Code, that states the possible sanction will not take effect if the interested party is not notified personally and the player was not notified. That is why Cheryshev was playing. 

"I spoke to the Federation on Wednesday and we will see what happens. The ruling will be made on Friday and our legal representatives will have something to say. We can say little more, tell the truth about what happened, be cautious and careful. We have talked over the course of the night at the club with everyone involved and there is no record."

Cadiz president Manuel Vizcaino, meanwhile, has confirmed the Segunda Division B club will take the issue to the RFEF (Spanish Football Federation).

"The board meeting has decided to make a complaint about the ineligible player Cheryshev, with pain in our heart," Vizcaino said at a news conference.

"We will report Real Madrid. It's a hard decision, but we have to act."