The club captain believes the Blancos are in for a difficult run in the cup, while assistant Aitor Karanka defended the referee despite several contentious decisions
Iker Casillas says Real Madrid’s performances in the Copa del Rey are helping to ease the pain of their Liga struggles, after recording a 2-0 win over Valencia in the first leg of their quarter-final.
Karim Benzema opened the scoring in the first half before an own goal from Jose Guardado doubled Blancos' advantage, despite plenty of attacking domination from the visitors throughout the quarter-final.
Casillas, however, preferred to focus on the recording of a confidence-boosting clean sheet, before admitting that a potential semi-final against Barcelona or Malaga will be tough.
"Playing the first leg at home, it was important to keep a clean sheet," the Spain goalkeeper told reporters after the victory.
"Valencia are a tough team and I am convinced that the return leg will be difficult. Our performance suffered, but the result is excellent.
"We have a complicated route in the Copa and we know it. If we qualify, we have a hypothetical clash with Barcelona or Malaga, which is fine.
"But the victory gives us confidence and helps us to forget the pain of our league form."
Madrid assistant coach Aitor Karanka then defended match officials - who had been criticised for several dubious offside decisions - before accepting that the result could easily have gone in los Che's favour.
"There were two offsides, and from neither of them did Valencia score," he said. "So you can't talk about the opponents being affected by these bad calls by the referee.
"In previous matches, bad decisions by referees had a direct impact on the result. This didn't happen tonight.
"But the result could have been different, both teams had many chances to score."