Barcelona began their LaLiga title defence with a convincing 6-2 defeat of Real Betis.
The Catalans are pursuing a third successive Spanish championship, and followed their recent Spanish Super Cup defeat of Sevilla with another one-sided win, owing largely to Luis Suarez's hat-trick.
Arda Turan gave Barca the lead in only the sixth minute from close range after Messi's cut-back, while Betis equalised through Ruben Castro's fine 21st-minute free-kick, but - when Lionel Messi restored Barca's lead in the 37th-minute from 25 yards - the hosts began to dominate.
Suarez scored the first of his three goals with an angled strike in the 42nd minute to make it 3-1.
He added his second in the 56th with a routine tap-in after being set-up by Messi, one minute before the Argentinian's second, from just inside the area and again after being gifted too much space.
Suarez's third came from a 20-yard free-kick as good as Ruben Castro's.
The Betis forward reduced the deficit with a powerful finish in the 84th minute, but it proved little more than a consolation to his team.
Sevilla twice recovered from going a goal down to secure a 6-4 home defeat of Espanyol in coach Jorge Sampaoli's first league fixture in charge.
The Argentinian had overseen three successive defeats, the first via a 3-2 scoreline against Real Madrid in the UEFA Super Cup. The second and third contributed to a 5-0 aggregate deficit over two legs against Barcelona in the Spanish Supercopa.
Espanyol, whose goals came from Pablo Piatti, Hernan Perez, Victor Sanchez and Gerard Moreno, led both 1-0 and 3-2.
The hosts' equaliser in first-half stoppage time, from Luciano Vietto to prevent Espanyol leading at half-time, seemed particularly influential.
His earlier goal had put them 2-1 up after Pablo Sarabia made the score 1-1.
Franco Vazquez, Wissam Ben Yedder and Hiroshi Kiyotake scored three times in 20 second-half minutes to take Sevilla beyond Espanyol's reach. Moreno scored the game's 10th goal with 11 minutes remaining.
There was also a 1-1 draw at Granada for Villarreal, whose new coach Fran Escriba oversaw his first league fixture.
The visitors took the lead in the 61st minute when Samuel Castillejo curled a left-footed free-kick inside the right-hand post and beyond goalkeeper Guillermo Ochoa.
Granada equalised just four minutes later. Ezequiel Ponce was gifted possession directly in front of goal after a corner, and he capitalised by scoring with a routine close-range finish.
