Barcelona exacted narrow revenge on Athletic Bilbao as Luis Suarez's lone strike earned them a 1-0 victory at San Mames on Sunday.
Jordi Alba returned in place of Jeremy Mathieu after recovering from a thigh injury, sustained in the 3-0 Gamper Trophy victory over Roma a fortnight ago.
Elsewhere, Claudio Bravo got the nod ahead of Marc-Andre ter Stegen in goal, Thomas Vermaelen replaced the suspended Gerard Pique and Rafinha filled in on the left wing in light of Neymar's unavailability and Pedro Rodriguez's departure.
In the other corner, Athletic, who recently demolished Barca 5-1 over two legs to claim their first major trophy in 31 years, made eight changes from the team who lost 3-2 to Zilina in the Europa League playoffs on Thursday.
Barca were expected to come out of the traps in a bid to avenge their Supercopa defeats, but they struggled to find their rhythm, with Athletic's high pressing particularly marking Lionel Messi out of the game for most parts.
Instead, the creative duties were left to Suarez in the first half as he fell under Mikel Balenziaga's challenge in the box. However, Messi's tame attempt to the right from the penalty spot was easily kept out by Iraizoz.
The Uruguayan continued to pose La Blaugrana's biggest threat, and he should have done better when his angled drive from close range was parried away by Iraizoz.
Nonetheless, Suarez finally broke the deadlock for Barca early after the restart as Alba's deep cross at the far post was volleyed home by the No 9, unmarked in the penalty area.
La Blaugrana then almost doubled their lead through substitute Sergi Roberto, who crashed a piledriver against the bar, before Messi got his mojo back, almost scoring a goal akin to his wonder solo strike in the Copa del Rey final as he dribbled past several Athletic jerseys but couldn't beat the custodian with his finish.
However, it was not all smiles for the Catalans as Dani Alves and Sergio Busquets both left the field of play with injuries, the latter departing on a stretcher.
Athletic Bilbao 0-1 Barcelona
Athletic Bilbao: Iraizoz; De Marcos, Elustondo, Laporte, Balenziaga (Boveda 50); Benat, Rico (Gurpegi 63); Susaeta, Eraso, Sabin (Ibai 63); Aduriz
Barcelona: Bravo; Alves (Sergi Roberto 19), Mascherano, Vermaelen, Alba; Busquets (Bartra 68), Rakitic, Iniesta; Messi, Suarez, Rafinha (Sandro 82)
Referee: Del Cerro Grande