MADRID (AFP) - Edgar Mendez's solo effort nine minutes from time sent Alaves into their first ever Copa del Rey final with a 1-0 semi-final, second leg win over Celta Vigo enough to progress by the same score on aggregate.
The visitors were left to rue a string of missed chances in the first leg as Mendez burst through the Celta defence before firing high past Sergio Alvarez to wild scenes of celebration at Mendizorrotza.
Alaves will have to beat Barcelona to lift the Cup for the first time, though, in May's final after the holders reached their fourth straight final with a 3-2 aggregate win over Atletico Madrid on Tuesday (Feb 7).
However, Alaves can take inspiration from a shock 2-1 win at the Camp Nou back in September in La Liga.
It is the first time Alaves, newly promoted to the top flight of Spanish football this season, have reached any final since losing out on the 2001 Uefa Cup 5-4 to Liverpool.
And it was a former Liverpool striker who threatened to thwart them once more as Fernando Pachecho made a fine early save to turn Iago Aspas' effort behind.
Neither side created many chances in a tense encounter, but Alaves made theirs count when Mendez latched onto Victor Camarasa's flick-on and drove past Hugo Mallo and Gustavo Cabral before unleashing a shot high into the far corner.