Barca beaten in Guardiola's debut

Midfielder Mario scored the only goal of the game to hand his side a famous victory over Barca, who spurned a handful of chances to equalize.

Samuel Eto'o and Lionel Messi hit the woodwork as Barca failed to avoid an embarrassing opening day defeat.

Elsewhere, Atletico Madrid overwhelmed Malaga 4-0, courtesy of a Diego Forlan brace. John Heitinga and Florent Sinama-Pongolle were also on the scoresheet.

Last season's runners-up Villarreal were held 1-1 by Osasuna, while Sevilla drew by the same scoreline at Racing Santander.