Real Sociedad defeated second-division club Mirandés 1-0 Wednesday to reach the Copa del Rey final for the first time in more than three decades.
Mikel Oyarzabal converted a first-half penalty to give Sociedad a 3-1 aggregate win. The two-time Copa champion had won the first leg 2-1 at home.
Sociedad, playing some of the most attractive soccer in Spain, will face either Granada or Basque Country rival Athletic Bilbao, who play on Thursday. Athletic won the first leg 1-0 in Bilbao.
Sociedad will be playing in the final for the first time since 1988, a year after it won its second title. The first came in 1909.
The loss ended a surprising run for Mirandés, a small club based in Miranda de Ebro, a city of about 35,000 people in northern Spain. It had eliminated first-division clubs Villarreal, Sevilla and Celta Vigo on its way to the semifinals.
Mirandés also made a memorable Copa run in 2011-12 before falling to Athletic in the semifinals.
Mirandés was trying to become the first second-division club to reach the final since Real Madrid's “B" team in 1980.
Sociedad eliminated Madrid in the quarterfinals with a 4-3 away win at the Santiago Bernabéu Stadium.
Sociedad's Basque rival Athletic Bilbao, the competition's second-most successful club behind Barcelona, eliminated the Catalan club in the last eight.
If the Basque clubs meet in the April 18 final in Seville, it would be the first time they play for the Copa title since 1910.
Granada is trying to reach its first Copa final since 1959, when it lost to Barcelona.
Oyarzabal scored Sociedad's winner in the 41st minute after a handball by Mirandés midfielder Mickael Malsa after a cross into the area.
Sociedad forward Alexander Isak had a goal disallowed for offside in stoppage time.