Overcoming Real Madrid's mental block against Barcelona will be the chief concern for coach Jose Mourinho when the teams resume their battle for supremacy tomorrow.
Real host their arch-rivals for a King's Cup quarter-final first leg having won 22 of their last 23 matches in all competitions, the one defeat being a 3-1 La Liga reverse at Barcelona's hands at the Bernabeu six weeks ago.
Mourinho has managed only one victory over Barcelona in eight attempts since taking the job two years ago, when Cristiano Ronaldo nodded home an extra-time winner in a 1-0 triumph in last season's King's Cup final.
Four defeats and three draws across four competitions make up the rest of the story between the two rivals but the coach goes into tomorrow's tie holding a five-point La Liga lead over the champions.
Mourinho has made it clear the league is this season's priority and he would be able to write off a King's Cup slip-up as irrelevant. However, the psychological impact of the clasico tussles could play a big role in each team's campaign.
"You'll have to ask the Madrid players if we have eaten into their morale," Barcelona's midfielder Xavi told a news conference yesterday. Winning or losing will have a big effect on a team's state of mind. The winner will receive a huge confidence boost."
Spanish international Xavi responded to questions about Ronaldo, who has gone off the boil in recent games and been whistled at disapprovingly by some sectors of the Bernabeu crowd since his below-par showing in last month's clasico.
The comparisons with Lionel Messi, crowned World Player of the Year for the third time last week, appear to weigh heavily on the Portuguese forward, who has scored three times in 10 clasicos compared to the Argentine's seven strikes over the same period.
"Messi always makes the difference," Xavi said. "The Bernabeu seems to be to his liking. He always rises to the occasion and we expect him to do the same again.
"Ronaldo, like all strikers, goes through runs of form. Sometimes the ball goes in, other times it doesn't, but it is clear he is capable of making the difference."
Ronaldo is La Liga's leading scorer, with an impressive 21 goals, but his anxious performances against Barcelona and a tense relationship with some of Real's fans mean the world's most expensive player will once again be the focus of attention.
"I have a routine before matches, like most players," Ronaldo told DT magazine. "I try to laugh, crack a few jokes, listen to house music.
"I don't put myself under pressure. If you do this, things go badly. I am this way whether I am preparing to play Barcelona or any other team. My mental strength is very important."
Mourinho has a doubt over the defender Pepe, who missed training on Monday with a bruised thigh, but Angel Di Maria is expected to return to the squad and could feature.
The Barcelona coach, Pep Guardiola, is without the injured David Villa, Ibrahim Afellay and Pedro, while Seydou Keita is away at the African Cup of Nations.
Tonight third-tier Mirandes, who have knocked out the La Liga sides Villarreal and Racing Santander so far, visit Espanyol. The 23-times King's Cup winners Athletic Bilbao are at home to 2003 winners Real Mallorca tomorrow and the final first leg will be a Valencia city derby played on Thursday. Levante, one of the revelations of the league season, are fourth just behind their neighbours Valencia and will make a visit to the Mestalla.