Athletic Bilbao have built up a four-goal lead in the Supercopa de Espana final after a comfortable first-leg victory against Barcelona at the San Mames.

A strike from Mikel San Jose and a second-half hat-trick from veteran forward Artiz Aduriz have put the Basque club in command ahead of the second-leg at Camp Nou.

Athletic Bilbao's defender Mikel San Jose celebrates after scoring during the Spanish Supercup first-leg football match Athletic Club Bilbao vs FC Barcelona at the San Mames stadium in Bilbao on August 14, 2015 © Getty Images

Bilbao almost took the lead on 11 minutes when Marc-Andre ter Stegen's misplaced clearance fell to the feet of Aduriz, and his shot at the near post needed to be tipped around by the German keeper.

However, they hit the front in dramatic style as another Ter Stegen clearance landed in the path of San Jose, who fiercely drove the ball back over his head and into the back of the net.

Barca then needed an alert Thomas Vermaelen, making his second start at the club since moving from Arsenal last summer, who beat Javier Eraso to Aduriz's threatening pass.

Athletic Bilbao's defender Mikel San Jose is congratulated by teammates midfielder Benat Etxebarria (L), midfielder Oscar de Marcos (3rd L) and defender Xabier Etxeita (R) after scoring during the Spanish Supercup first-leg football match Athletic Club Bi © Getty Images

The Blaugrana nearly scored an equaliser on the stroke of half time, but Gorka Iraizoz was able to reach Lionel Messi's curling free kick to tip it away from danger.

Luis Enrique's men continued to pose a threat and went close again as Pedro got the better of San Jose before striking the crossbar.

Instead, Bilbao doubled their advantage as Aduriz showed the goal-scoring prowess that saw him get 26 goals last term by rising to meet Sabin Merino's tantalising cross before powering his header beyond the reach of Ter Stegen.

Pedro Rodriguez of FC Barcelona competes for the ball with Markel Susaeta (L) and Oscar de Marcos of Athletic Club during the Spanish Super Cup first leg match between FC Barcelona and Athletic Club at San Mames Stadium on August 14, 2015 © Getty Images

Athletic went three up just after the hour mark as Dani Alves's poor attempt at a clearance fell to the feet of Aduriz and the 34-year-old's low strike found the bottom corner of the Barca net.

Moments later, the hosts were awarded a penalty as Alves dived into the man he was marking and Aduriz duly sent Ter Stegen the wrong way.

The second leg takes place at Camp Nou on Monday evening.