Osasuna knocked reigning champions Athletic Bilbao out of the Copa del Rey on Thursday with a 3-2 win in San Mames after a thrilling cup tie that either side could have won.

Osasuna had goalkeeper Sergio Herrera to thank for three saves to deny Gorka Guruzeta and twice frustrate Inaki Williams, before they opened the scoring with a swift counterattack.

Jesus Areso crossed from the right for Aimar Oroz to smash into the top corner in the 41st minute to put Osasuna ahead and they were 2-0 three minutes later with Ante Budimir's penalty.

Athletic needed a goal and got it in injury time when Nico Williams volleyed home making it 2-1 on the stroke of halftime.

Oscar de Marcos made it 2-2 when he ran onto Mikel Jauregizar's pass to score with an angled shot and Athletic threatened to turn around the game.

However, it was Budimir who won it for Osasuna, poaching the winning goal with 20 minutes left to play.

In Thursday's second early cup tie, Real Sociedad beat Rayo Vallecano 3-1.