Messi helped 10-man Barcelona start the Spanish league with a 3-0 win over Elche in the debut of coach Luis Enrique, with the Argentina star looking eager to put last season's disappointments behind him.
Messi used a burst of speed to dribble free of a pack of opponents before slotting in Barcelona's first goal in the 41st. Barcelona then lost Javier Mascherano to a direct red card when he fouled Elche's Garry Rodrigues with only goalkeeper Claudio Bravo to beat.
But 18-year-old Munir El Haddadi, starting for the injured Neymar, scored seconds after halftime before Messi got his second goal in the 63rd after again sidestepping a group of defenders.
Elsewhere, promoted Eibar beat Real Sociedad 1-0 for a winning debut in the first division, and Celta Vigo beat Getafe 3-1.