Athletic Club were crowned Supercopa de España champions after beating Barcelona 3-2 on Sunday.
Goals from Oscar De Marcos, Asier Villalibre and Iñaki Williams were enough to secure victory despite Antoine Griezmann scoring twice.
Despite their poor start, Barcelona went ahead through Antoine Griezmann who finished well after neat interplay between Lionel Messi and Jordi Alba.
But Athletic were not deterred and responded immediately when Oscar De Marcos fired past Marc André ter Stegen before half time.
Los Leones thought they took the lead after 55 minutes when Raul García rose highest to head home, only for his effort to be correctly ruled out for offside.
Barça looked to have scored their winner when Griezmann netted another Alba cross, before Asier Villalibre struck a 90th minute equaliser to force extra time.
Clearly reinvigorated by their late leveller, Athletic started extra time well and scored their third through Iñaki Williams – who curled a stunning strike straight into the top corner.
Lionel Messi was sent off deep into injury time for raising his hands on Villalibre, with the Basque underdogs holding on for another historic night.