Athletic Bilbao and Atletico Madrid overcame German opposition to reach the Europa League semi-finals on Thursday while fellow Spaniards Valencia joined them by demolishing AZ Alkmaar.
Sporting completed an all-Iberian lineup by knocking out Metalist Kharkiv, who missed a penalty in a 1-1 draw in Ukraine allowing the Portuguese side go through 3-2 on aggregate.
Athletic, Manchester United's conquerors in the previous round, played more of the entertaining football which is a hallmark of their eccentric coach Marcelo Bielsa as they drew 2-2 at home to Schalke 04 to qualify 6-4 on aggregate.
Atletico Madrid won 2-1 at Hanover 96 with an 87th minute winner from Radamel Falcao, last season's top scorer in the competition playing for champions Porto, to complete a 4-2 aggregate win.
Adil Rami scored two early goals to set Valencia on their way to a 4-0 victory over AZ Alkmaar as they comfortably overturned a first-leg deficit to win 5-2 on aggregate.
Spain also has Barcelona and Real Madrid in the last four of the Champions League and there is now a possibility that both European finals this season will be all-Spanish affairs.
Atletico Madrid face Valencia in the semi-finals while Athletic Bilbao, enjoying their best European campaign since reaching the final of the old UEFA Cup in 1977, play Sporting.
