Real Sociedad have waited almost a year to defeat fierce Basque rivals Athletic Bilbao 1-0 in the delayed final of the 2020 Copa del Rey - securing a first major title in more than three decades.
Mikel Oyarzabal's penalty earned Sociedad their third Spanish Cup trophy.
The final was delayed because of the coronavirus pandemic, and continued to be pushed back in a bid to let fans attend, but they are still not permitted at matches in Spain.
Athletic have another chance to lift the trophy in this season's cup final on April 17, against Barcelona, also at Seville's La Cartuja stadium.
They last reached the final in 2015, where they were beaten by Barca, and despite sitting second in the list of Copa winners with 23 triumphs they have not won it since 1984.
A tight game was opened up shortly after the hour mark when Inigo Martinez fouled Portu in the area as he burst through on goal, leading to a penalty and a red card for the Athletic defender.
The expulsion was revoked after a lengthy VAR review but that did not prevent Oyarzabal firing home from 12 years to put Real Sociedad ahead.
The goal proved decisive to earn La Real their first Copa del Rey win since 1987, a bitter blow for Martinez, who left his boyhood club Sociedad for Athletic in 2018.
"It's a beautiful day where you remember everything," Oyarzabal said.
"Giving this to our fans was the best thing that we could do...This is for everyone, it's incredible.
"We are champions and we'll celebrate it without a doubt."
Athletic have now lost five cup finals since they last lifted the trophy.
"It's a really big blow for us to take," Athletic right-back Oscar de Marcos said.
"Finals are hard when you lose, whoever the opponent is.
"It's a very sad day for us."