Barca lost the first leg 2-0 but Ousmane Dembele’s thumping early strike put them ahead at the Camp Nou before Gerard Pique headed home in added time to level the tie, after Sevilla’s Lucas Ocampos had missed a penalty.

Martin Braithwaite’s extratime header completed a 3-2 aggregate win and continued a remarkable journey in this year’s Copa, in which Barca needed extratime to knock out third division Cornella 2-0 and came from behind to beat second division Rayo Vallecano 2-1.

They were 2-0 down at Granada until the 88th minute in the quarterfinals but levelled with two late goals before winning 5-3 after extratime.

“We always believed, we have never thrown this cup away,” Koeman told reporters.

“It’s a question of mentality, and as a coach I can’t ask for any more from my team than what I saw tonight. We kept on fighting in extratime, it was incredible. I’m very satisfied with how hard we worked tonight. We deserved the win.”

Unlike previous coaches, Koeman has prioritised the Copa del Rey and rested players in league matches to keep them fresh for cup games, saying the competition was Barca’s best chance of a trophy due to Atletico Madrid’s dominance in La Liga and the fierce competition of the Champions League.

“I’m very proud. It’s an important moment for the team and for me. Because if you win a game like this you are seen as a good coach but if you lose you are seen as very bad,” he added.

“This team is very strong physically and mentally. We can’t always play great football but if you have the ball you can always create opportunities. What we did tonight was something extraordinary.”