Real Madrid's Isco (R) is challenged by Cadiz's Jon Ander Garrido during their Spanish King's Cup round of 32 first leg soccer match at Ramon de Carranza stadium in Cadiz, southern Spain, December 2, 2015. [Photo/Agencies]

MADRID - Real Madrid face almost certain expulsion from the Spanish Kings Cup knockout competition after fielding an ineligible player in their third round first leg tie away to Cadiz on Wednesday night.

The club started the game with Dens Cheryshev in their starting 11 despite the fact the Russian was suspended for having picked up two bookings in the competition while playing for Villarreal last season.

Cheryshev even scored the first goal of Real Madrid's 3-1 win, with Isco scoring Madrid's other two goals, but that could be worth nothing after Cadiz President Manolo Vizcaino confirmed after the game that his club would appeal against the result.

If the Spanish Football Federation (RFEF) accept the appeal, and there is a precedent from a game between Osasuna and Mirandes in the same competition, they will have no option other than to expel Real Madrid from the tournament.

Real Madrid Director of Institutional Relations, Emilio Butragueno insisted the club had not been informed of Cheryshev's suspension by either Villarreal or the RFEF, while coach Rafa Benitez, who suffered a similar mishap while coaching Valencia in 2001 said he had substituted the Russian "as an act of good faith" as soon as he discovered the error, but that will almost certainly not be enough to save one of the favorites for this year's tournament from a humiliating and totally avoidable exit.