Alaves reached the Copa del Rey final for the first time in their 96-year history with victory over Celta Vigo in their semi-final second leg.
Winger Edgar Mendez scored the only goal of the two games when he lifted the ball over keeper Sergio Alvarez and into the net in the 83rd minute.
Former Liverpool player Iago Aspas went close for Celta with a shot tipped away by goalkeeper Fernando Pacheco.
Alaves play Barcelona, who knocked out Atletico Madrid, in the final in May.
They beat Barca 2-1 at the Nou Camp earlier this season and will host Luis Enrique’s side on Saturday in La Liga.
Alaves’ only other appearance in a major final came in 2001 when they were beaten 5-4 by Liverpool in the Uefa Cup.
“We’re going to enjoy tonight and we’ll try to go for glory in May but we’ve already made history,” Alaves captain Manu Garcia said.
Source: BBC SPORTS