Captain Iker Muniain scored the only goal as Athletic Bilbao defeated Granada 1-0 in the first leg of their Copa del Rey semi-final on Wednesday.
Muniain, 27, had been red-carded in his team’s 2-1 defeat to Real Sociedad in La Liga at the weekend.
However, he was the toast of the city Wednesday when he latched onto a cross from Inaki Williams just three minutes before the interval to score the game’s only goal.
Athletic coach Gaizka Garitano named the same team which shocked Barcelona in the quarter-finals last week and they will consider themselves unfortunate not to have won by a greater margin on Wednesday after having two strikes ruled out for offside.
The second, scored off a fine volley in the 61st minute by Ander Capa, needed an intervention by VAR.
Athletic Bilbao won the first Copa del Rey in 1930 with a 3-2 win over Real Madrid.
With 23 titles, they are second on the all-time list to Barcelona who have triumphed 30 times.
However, their most recent success was back in 1984 after a 1-0 win over Barca.
The second leg of the semi-final takes place on March 5.
Thursday sees the first leg of the second semi-final with Real Sociedad taking on second division Mirandes.