The Catalan giants' treble hopes faded away with a 3-0 second-leg defeat to Roma earlier this month, seeing them crash out of the Champions League at the quarter-final stage on away goals.
"To win the Copa del Rey would be a good way to put the Champions League slip-up behind us," he said at his pre-match press conference. "To win with Barcelona is an obligation; the Champions League, La Liga, the cup and this is always the way with big teams. The pressure is the same with other finals; you have not won the title as you still have to play the final and there are two teams involved.
"We may be the favourites but you still have to play. In the Champions League we were favourites and we didn't go through. I never thought when I was with Athletic that to beat Barcelona was a miracle but an opportunity and that is what the situation is tomorrow.
"I am not looking for excuses, it is true that with the cup games in January and February it saw draws like against Getafe and Espanyol but we will not say that tiredness was the reason for what happened in the Champions League. We lost for other reasons.
"The 2-2 [draw with Sevilla last month] is a result for us to look at and a warning about what can happen in tomorrow's game. They have good players that can win the match in any moment. We suffered a lot in that match and it was Sevilla that were closer to winning."
Sevilla have been unable to win any of their last six meetings against Barcelona, losing five and drawing one of those.