Although claiming that Barca's recent form will not hinder their chances of lifting the trophy tomorrow, Casillas is optimistic that Real will have too much for Gerardo Martino's side.
"We think we are going to do it," he told reporters. "It won't be easy, it will be an exciting match with great players and we need to believe in our chances and our way of playing.
"Personally I'm not thinking about Barcelona's last week at all, regarding their defeats in the Champions League and La Liga.
"It's different for the two teams, anything can happen in a Final. Now they have two competitions to play for. One will be difficult for them to win and the other is this final."
Tomorrow's encounter at the Mestalla is scheduled to kick off at 8.20pm.