MADRID (AP) -- Basque Country rivals Real Sociedad and Athletic Bilbao have a chance to reignite one of Spain's fiercest rivalries - if they can both reach the Copa del Rey final for the first time in more than a century.
The two clubs are the only semifinalists that have won the competition before, although not in the last three decades.
A revamped format with single elimination games in all stages except the semifinals proved costly for Spain's top clubs. Real Madrid and Barcelona couldn't make it past the quarterfinals and Atletico Madrid was eliminated before that, beaten by a third-division club.
Second-division club Mirandes and Granada are also in the semifinals and will be looking for their first Copa del Rey title. Mirandes has never even reached the final, while Granada made it once more than six decades ago but lost to Barcelona.
Sociedad plays at Mirandes on Wednesday holding a 2-1 lead from the first leg at home. Athletic visits Granada on Thursday with the advantage of a 1-0 win in the first leg in Bilbao.
Athletic, which only fields players born or raised in the Basque region, is the competition's second-most successful club with 23 titles - behind Barcelona - but its last triumph was in 1984. Sociedad is a two-time champion, with its last title coming in 1987.
Sociedad and Athletic have met in the Copa del Rey final only once, back in 1910 when Athletic won the deciding match of a three-team mini-tournament.
''We know what it means to our fans to make it to the final,'' Athletic defender Inigo Martinez said. ''It would be huge. We will need to work hard to be able to advance.''
Athletic is trying to make it to its fourth Copa del Rey final in the last 12 years. It lost to Barcelona in 2009, 2012 and 2015. This time, the team eliminated the Catalan club 1-0 in the quarterfinals at home.
Sociedad, playing some of the most attractive soccer in Spain at the moment, is looking to reach its first final since 1988. The team from San Sebastian eliminated 19-time champion Real Madrid in the quarterfinals with a 4-3 win at the Santiago Bernabeu Stadium.
''It's amazing what we have been able to achieve this season,'' Sociedad coach Imanol Alguacil said. ''Let's see if we can keep this going until the end.''
The Spanish soccer federation revamped the tournament in part to create more dates on the calendar. The Spanish Super Cup was played in a ''Final Four'' format this season, with more matches required.
The new single-elimination format made most games more exciting, and gave smaller clubs greater chances of advancing against more traditional opponents.
It's the first time in a decade that neither Barcelona nor Madrid made it to the last four. Barcelona, a 30-time champion, made the final the last six years in a row, winning four. The last time a team other than Barcelona, Madrid, Sevilla, Valencia or Atletico Madrid won the tournament was when Espanyol lifted the trophy in 2006.
Valencia, the defending champion, was eliminated in the quarterfinals by Granada, which made it to its only final in 1959.
Mirandes is a small club based in Miranda de Ebro, a city of about 35,000 people in northern Spain. It reached the final four by eliminating first-division clubs Villarreal, Sevilla and Celta Vigo. The club has never played in Spain's top division, but it also made a memorable cup run in 2011-12, beating Villarreal, Racing Santander and Espanyol before falling to Athletic in the semifinals.
This year's final will be played on April 18 in Seville.
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