The Spain international believes that his Basque side will have their chances to surprise the Blaugrana and coming out victorious in the Copa del Rey decider
The right-back conceded that Barca will start the match as favourites, but is confident that Athletic will get their opportunities as long as they play their own game.
"Barcelona are obviously the favourites, because of the players they have and because of what they have achieved," Iraola was quoted as saying by El Mundo Deportivo.
"But I believe in our team. We can compete if we play our own game, and will get our chance. We have to belief in ourselves.
"Barcelona will try to pin us back in our own half. However, we want it to be a game that goes from one end to the other."
Friday's encounter kicks off at 22.00CET.