Real Madrid have been disqualified from the Copa del Rey after fielding the suspended Denis Cheryshev in the first leg of their round-of-32 tie against Cadiz on Wednesday.
The Russia midfielder started and scored in the 3-1 victory despite being yet to serve a ban for receiving three yellow cards in last season's competition when on loan at Villarreal.
Cadiz submitted an official complaint to the Royal Spanish Football Federation (RFEF) after the match, but Madrid insisted they had not been notified that the player was ineligible and were therefore not to blame.
However, the RFEF announced on Friday that Madrid have been expelled from the competition with immediate effect.
"Real Madrid have been found guilty of fielding an ineligible player, Denis Cheryshev, in the home match against Cadiz on December 2," a statement read.
"The outcome of the Copa del Rey [tie] has consequently been decided in favour of Cadiz, with an additional fine of €6,001 for Madrid as per article 76 of the disciplinary code of the RFEF.
"Cheryshev's one-match suspension has been served in the game in question.
"This decision can be appealed with the Appeals Committee within 10 days of the notification of the verdict."
Speaking on Thursday following a board meeting, Madrid president Florentino Perez had said: "Madrid have not named an ineligible player. This is the opinion after consulting the legal services of Real Madrid.
"After analysing what happened, the penalty for three yellow cards should not be considered effective because nobody told the player of his punishment, as stated in Article 41 [of competition regulations].
"The sanction is not effective, and even if it were, we believe it would be considered void with the application of the final paragraph of section 12: 'At the end of the third round of the Copa del Rey, there will be a complete cancelling of penalty cycles for all concerned'.
"We don't believe anyone acted negligently. This is our conclusion. Cheryshev is calm. He played because he was convinced he was able to."
Perez had also confirmed the club would be appealing any sanction, saying: "We will certainly take it to the TAD [Spain's Administrative Court for Sport], because we have a duty to defend what we believe is our right.
"If there had been any negligence by anyone, any notification that had gone astray or anyone who had not acted correctly, we would acknowledge that and we would apologise and we would take the measures we have to take. But the fact is that, quite honestly, it was impossible for us to know about it."