Barcelona let a late lead slip as they were held to a 2-2 draw at Estadio El Sadar by newly-promoted Osasuna.
The hosts broke the deadlock after less than seven minutes as wideman Brendan Thomas beat Clement Lenglet before clipping a ball across to the unmarked Roberto Torres, the striker rifling his volley past a helpless Marc-Andre ter Stegen.
Ernesto Valverde's men proceeded to dominate possession and dictate play from deep, yet they rarely threatened as Osasuna made it to half-time with their lead still intact. Arguably, Los Rojillos looked likeliest to grab the game's second goal, offering an aerial threat at corners.