La Liga champions Barcelona began the new campaign with a 3-0 win over Alaves on Saturday with the help of a spectacular under-the-wall free kick from Lionel Messi, who scored twice, and a curling shot from substitute Philippe Coutinho.
Barca had dominated the late kick-off at a quiet Nou Camp but again struggled to convert chances against a shrewd Alaves, who are the last team to win a league game at the Catalans' home, beating them 2-1 in 2016 and nearly repeating that feat last season before losing 2-1.
Messi had clanged the crossbar in the first half from a set- piece and Ousmane Dembele forced visiting goalkeeper Pacheco to make an impressive save while Luis Suarez looked immobile and ineffective.
Barca coach Ernesto Valverde brought on Coutinho at the start of the second half for Nelson Semedo, dropping Sergi Roberto from midfield to defence to give the team more creativity in a bid to open up the stubborn Basque side.
Barca looked more incisive and dangerous but it still took a moment of genius from all-time top scorer and new captain Messi to break the deadlock.
The Argentine took Alaves by surprise by rolling the ball under the defensive wall and past a baffled Pacheco, recalling
a similar strike against Girona last season and bringing the Nou Camp to its feet.
It was also the 6,000th goal Barca have scored in La Liga.
"I had no idea he was going to shoot like that, for us it's spectacular that he has such a range of options," said Barca midfielder Sergio Busquets.
"Sometimes in games like this you have to just wait for Leo to go and do his thing," added Sergi Roberto.
"The first time he hit the bar, the second time, goal number 6,000."
Record signing Coutinho sealed the points, finishing off a slick passing move by dribbling into the area and curling the ball home.
But it was Messi, the top scorer in La Liga last season with 34 goals, who had the final say, chesting down a cross from Suarez and holding off a defender before stroking into the near corner with the final kick of the game.
Barca joined Levante and Real Sociedad on three points at the top of the table, with Real Madrid hosting Getafe on Sunday and Atletico Madrid visiting Valencia on Monday.
Earlier on Saturday, Real Sociedad capitalised on two defensive errors to come from behind and win 2-1 at Villarreal, who saw Santi Cazorla make his first competitive appearance since October 2016 after recovering from a serious foot injury.
Celta Vigo were held to a 1-1 draw by Espanyol, while on Friday Levante pulled off a surprise 3-0 win at Real Betis.
Mbappe brace secures comeback win for PSG
World Cup winner Kylian Mbappe scored twice as champions Paris St Germain completed a second-half comeback to secure a 3-1 win over En Avant Guingamp in Ligue 1 on Saturday.
Belgium international Thomas Meunier returned to a youthful PSG side while Mbappe was benched as the visitors' quest for two wins in as many games got off to a poor start.
Guingamp held their own in front of a vociferous home crowd in the first half and forced an impressive save from goalkeeper Gianluigi Buffon to deny Marcus Thuram in the 14th minute.
Guingamp winger Marcus Coco capitalised on PSG right back Colin Dagba's error and played in striker Nolan Roux, who slotted past Buffon to give the hosts a shock lead.
Guingamp continued to pile on the pressure as PSG struggled with defensive errors and lacked attacking fluidity.
France international Mbappe replaced Timothy Weah at the start of the second half as PSG took control of the match, with Neymar winning a penalty in the 53rd minute and converting it to equalise.
A resurgent PSG then dominated proceedings and created numerous chances before Mbappe scored his opening goal of the season in the 82nd minute and he soon doubled his tally to seal the win.
Striker Radamel Falcao missed a penalty as a wasteful AS Monaco were held to a goalless draw with LOSC Lille in their first home league match of the season.
Monaco, the only team to win the league title other than PSG in the last five seasons, failed to convert their chances in the opening half while Lille rarely troubled Diego Benaglio's goal.
Skipper Falcao, who notched a goal and an assist in Monaco's opening victory at Nantes, missed the hosts' best chance in the 67th minute, when he won a penalty but failed to convert it as Lille goalkeeper Mike Maignan pulled off a good save.
Monaco continued to push for a breakthrough but Lille held on to secure a point.
PSG top the standings, followed by Dijon and Stade Reims, who climbed to third after Friday's 1-0 win over Olympique Lyonnais.
Monaco and Lille are fourth and fifth while a second consecutive defeat left Guingamp in 17th position.