Isco hopes Real Madrid will play a Copa del Rey second-leg against Cadiz "for the good of football" after coach Rafael Benitez fielded Denis Cheryshev despite the player being ineligible through suspension.
Cheryshev, scorer of the opening goal in the 3-1 win on Wednesday, was suspended for the cup clash due to picking up three yellow cards while playing for Villarreal in last season's competition.
However, the Russian lined up for the clash at Estadio Ramon de Carranza, eventually being replaced 45 seconds into the second half.
Attacking playmaker Isco remained optimistic Real would not face expulsion from the competition.
"I hope, for the good of football, we will play a second leg," the 23-year-old told Canal+. "It was a good match against a strong team.
"I heard of it [Cheryshev's ineligibility] in the second half. This is the directors' responsibility, so they have to work with it. We did our job, [to] win."
A precedent has already been set for this case, with Osasuna thrown out of this year's competition for fielding an ineligible player against Mirandes.
Cadiz president Manuel Vizcaino has confirmed the Segunda B club will report Real Madrid to the Royal Spanish Football Federation (RFEF).