Mourinho said in the wake of Real's shock 2-1 defeat to Getafe that he expects his players to perform, but is not too bothered about the result.
"For me the only problem is if the difference in performance between the first two games and the last match remains, that's the only problem," Reuters quotes Mourinho as saying.
"Win the Super Cup, not win the Super Cup. Beat Barca, not beat Barca. None of that is important to me right now.
"My priority right now is to know whether the attitude we had against Getafe was a chance happening or whether it's a situation that has had consequences on the psychological profile of some players. That for me is the fundamental thing for tomorrow."
Barcelona are currently 3-2 up in the Super Cup with the return leg to play.