MADRID, Nov. 28 (Xinhua) -- Both Barcelona coach Pep Guardiola and his Real Madrid counterpart Manuel Pellegrini have injury doubts ahead of Sunday's clash in the Camp Nou stadium.

    Although Cristiano Ronaldo played 20 minutes of Real Madrid's dull 1-0 win over Zurich in the Champions League, he didn't appear to be fully fit.

    The Portuguese international says he wants to start in the CampNou, but whether his is full fit yet is still a doubt.

    Pellegrini will probably take a risk on his star player. ShouldRonaldo not start and Real Madrid then lose, the consequences would be serious for the coach, whose job is still in danger after Real Madrid's Cup defeat to Alcorcon.

    There is also a doubt over the fitness of central defender RaulAlbiol, who damaged his right knee in the Zurich game. If he does not recover Ezequiel Garay will step into central defense.

    The remaining doubt in the Real Madrid side is whether Karim Benzema or Gonzalo Higuain starts in attack. If the decision was down to recent form, Higuain would start, but if other factors, such as the money Real Madrid spent on Benzema, play a role, then the Frenchman will start.

    Meanwhile in Barcelona, everything depends on the fitness of Leo Messi and Zlatan Ibrahimovich.

    Messi strained his groin last weekend and was on the bench for Barcelona's impressive 2-0 win over Inter Milan on Tuesday. Ibrahimovich was also on the bench as he tries to shake off the effects of a hamstring problem.

    It was clear that Barcelona coach Pep Guardiola didn't want to risk either of his players in midweek and it is uncertain whether either will start on Sunday.

    Friday's training session showed the Swede to be closer to full fitness than Messi, who could start on the substitutes' bench with Thierry Henry playing on the right of the Barcelona attack and Andres Iniesta on the left.

    Meanwhile the only other doubt is whether Sergio Busquets or Toure Yaya will partner Seydou Keita and Xabi Hernandez in midfield.

    Real Madrid will be keen to mark Xabi out of the game and once again it looks as if the Spain international will be vital to the outcome of this match.

    Last season Barcelona won 2-0 in the Camp Nou before humiliating Madrid 6-2 in the Santiago Bernabeu.

    At the moment, however Real Madrid leads the BBVA Primera Liga by one point and Pellegrini's men know that a draw would be a good result.