BARCELONA - Real Madrid could be thrown out of the King's Cup for playing an ineligible player in their 3-1 victory over Cadiz on Wednesday after Barcelona routed lower league Villanovense 6-1 to reach the last 16.
Real's Denis Cheryshev received a third yellow card playing for Villarreal in the semi-finals last season but he has not served the resulting ban and the Madrid club are set to be thrown out of the competition, Spanish media reported.
Cheryshev scored the opening goal before being substituted at halftime and Isco struck twice for Real against the third- tier side who pulled a late goal back through Enrique Marquez.
The potential disqualification heaps more pressure on Real Madrid who lost 4-0 at home to arch-rivals Barca in La Liga last month and are six points behind them in the standings after 13 games.
"It is a complicated situation. Nobody at the club knew about the suspension," Real director Emilio Butragueno told reporters.
"Nobody at the club was informed by the federation, we received nothing from Villarreal and Cheryshev didn't know about the ban."
Youngster Sandro Ramirez hit a hat-trick and Munir El-Haddadi struck twice for a Barcelona second-string side who tore apart lower league Villanovense 6-1 to book the holders a place in the last 16.
With big names including Lionel Messi, Neymar and Luis Suarez rested, it was a chance for Barca's lesser lights to shine after a goalless first leg and Sandro and Munir took full advantage with deadly performances.
It was always going to be a tough task for third-tier Villanovense but keeper Jose Fuentes could have done better with Dani Alves's opener after four minutes and he gave the ball straight to Sandro who scored.
Juanfran Guarnido pulled a goal back after 29 minutes but two minutes later Sandro pounced again. Barca piled on the misery after the break with Munir scoring twice and Sandro getting another in between.
The tie was brought forward due to Barca's involvement in the Club World Cup this month and the other first-leg matches take place this week.
"Sandro and Munir scored again but they have a lot of improving to do," Barca coach Luis Enrique told reporters.
"They are good friends and have a great understanding. They were always good strikers and I have a lot of belief in them."
Luis Enrique fielded an inexperienced attack but he took fewer risks in defence which included Marc Bartra and Thomas Vermaelen at centre half while Javier Mascherano provided solidity in the centre of the pitch.
Barca had been unsettled by the direct approach from Villanovense in the first keg but at home they got the perfect start with a drive from distance by Alves which looped over a static Fuentes and into the goal.
Barca have hit a rich streak of form since the first game and it showed with their confident passing while they were aided by an even clearer error from Fuentes who inexplicably played the ball straight to Sandro who slotted home.
Juanfran was given too much space on the edge of the Barca area and pulled a goal back with a precise shot into the top corner.
Sandro, though, responded almost immediately with a clinical finish with the outside of his right boot following a pass from Aitor Cantalapiedra.
Barca continued to open up Villanovense at will in the second half with Munir heading in a Jeremy Mathieu cross. Sandro fired home a loose ball in the area and Munir wrapped up the scoring following a back-heel from Sandro in the box.