Athletic have been through years of heartache, having lost their previous six consecutive Spanish cup finals and a Europa League final to Atletico Madrid in 2012.
Bilbao are the second most successful team in the history of the Copa del Rey, their 23 titles behind only Barcelona's 31, their most recent coming in 2020-21.
Sergi Darder fired the decisive spot-kick as Real Mallorca beat Real Sociedad 5-4 on penalties to book their place in the Copa del Rey final on Tuesday.
Inaki Williams raced back from Africa to face Barcelona in the Copa del Rey and sent Athletic Bilbao into the semi-finals by scoring a crucial goal in their 4-2 extra-time triumph on Wednesday.
Defeat snapped Madrid's 21-match unbeaten run.
"It's a positive result, our play was positive in many moments, and we're in the last 16," Barca coach Xavi told Movistar.
Atletico Madrid progressed with a 3-1 win at third-tier Lugo after Memphis Depay struck twice, while Real Betis were knocked out in a 1-0 defeat by Alaves.
"This Copa arrived at an important moment, we came through very tricky ties, it's a deserved prize against strong opponents," added the coach
Carlo Ancelotti's Madrid earned their 20th Spanish Cup in their 40th final, ending a nine-year wait to lift the trophy again
Athletic have been through years of heartache, having lost their previous six consecutive Spanish cup finals and a Europa League final to Atletico Madrid in 2012.
Bilbao are the second most successful team in the history of the Copa del Rey, their 23 titles behind only Barcelona's 31, their most recent coming in 2020-21.
Sergi Darder fired the decisive spot-kick as Real Mallorca beat Real Sociedad 5-4 on penalties to book their place in the Copa del Rey final on Tuesday.
Inaki Williams raced back from Africa to face Barcelona in the Copa del Rey and sent Athletic Bilbao into the semi-finals by scoring a crucial goal in their 4-2 extra-time triumph on Wednesday.
Defeat snapped Madrid's 21-match unbeaten run.
"It's a positive result, our play was positive in many moments, and we're in the last 16," Barca coach Xavi told Movistar.
Atletico Madrid progressed with a 3-1 win at third-tier Lugo after Memphis Depay struck twice, while Real Betis were knocked out in a 1-0 defeat by Alaves.
"This Copa arrived at an important moment, we came through very tricky ties, it's a deserved prize against strong opponents," added the coach
Carlo Ancelotti's Madrid earned their 20th Spanish Cup in their 40th final, ending a nine-year wait to lift the trophy again
Real Madrid coach Carlo Ancelotti thinks the Copa del Rey final against Osasuna on Saturday could be his last -- although he has thought the same in the past and been wrong, he explained Friday.