Ronaldo has been whistled by home supporters at Real's Bernabeu stadium since a poor performance in last month's La Liga 'Clasico' against arch-rivals Barca.
The former Manchester United player reacted by refusing to celebrate his goal in a 5-1 win over Granada and makes his first home appearance since then in Wednesday's quarter-final first leg.
At a news conference on Tuesday, a cantankerous Mourinho said Ronaldo's performance in Saturday's 2-1 win at Real Mallorca had been his best of the campaign despite the fact that he had not added to his 21 league goals.
"He worked like an animal and did exactly what the team needed," Mourinho said.
"He doesn't need to score or be man of the match every time. I told him nobody can touch him after the way he worked in the second half.
"When the team wins everyone is responsible and when they lose everyone is responsible for that too. Simple."
ATTACKING GAME
Mourinho has managed only one victory over Barca in eight attempts since taking the Real job at the end of the 2009/10 season, when Ronaldo nodded an extra-time winner in a 1-0 triumph in last season's cup final.
The last time the teams played each other over two legs in the Spanish Cup, in the 1996/97 campaign, the former Inter Milan and Chelsea manager was assistant coach at Barca and the Catalan club went through 4-3 on aggregate.
Appearing at a later news conference in Barcelona, Mourinho's counterpart and former colleague Pep Guardiola said he had no plans to curb his players' attacking game.
"I have always thought going to the Bernabeu and playing cautiously makes the games last an eternity and in the end Madrid never fail to score," said the former Barca and Spain midfielder, who turns 41 on Wednesday.
"The only way to win this tie is to keep the ball and play a solid positional game to stop their counter-attacks," he added.
"If we play with the fact that there is a return leg in mind we could get burned."
Mourinho refused to give any details about his tactics for the game, saying that whatever he decided would no doubt be criticised in the Spanish media.
Angel di Maria, who has not played since injuring himself in the final training session of 2011, will be named in the squad and a decision will be made on his fitness on Wednesday.
"The [Spanish] league is the priority," Mourinho said. "But tomorrow is also a great match and you want to do the best possible and use all the players if they are available."
Guardiola will be without Spain forward Pedro who has a hamstring strain.
