Barcelona made it two wins from their opening two La Liga games as Ivan Rakitic’s first-half header earned them victory at Athletic Bilbao.
The Croatian scored in the 21st minute when he arrived at pace to power in Arda Turan’s cross from the left.
Lionel Messi, Luis Suarez and Turan also went close for the champions.
Barca keeper Marc-Andre ter Stegen almost paid for a terrible pass, and Athletic’s Raul Garcia and Inaki Williams went close for Bilbao.
Sunday’s win sees coach Luis Enrique’s side join El Clasico rivals Real Madrid and early leaders Las Palmas on six points after two games of the new season.