The Spanish football record champion Real Madrid failed early in the Copa del Rey and has to wait for its first title win since 2014.
At Athletic Bilbao, the 19-time cup winner deservedly lost 0-1 (0-0) in the quarter-finals. The Basques had already knocked out FC Barcelona in the previous round.
Alex Berenguer (89th) scored the decisive goal for the underdog. Former world champion Toni Kroos was in the starting XI for Madrid and was substituted in the 76th minute.
Also in the semifinals is Betis Sevilla, who won 4-0 (1-0) at Real Sociedad. FC Valencia and Rayo Vallecano had already prevailed in their quarter-final duels on Wednesday.
The next pairings will be drawn on Friday.