Clever Messi free kick helps Barca to opening win

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.

Soccer Football - La Liga Santander - FC Barcelona v Alaves - Camp Nou, Barcelona, Spain - Aug 18, 2018 Barcelona's Jordi Alba has a shot at goal. Reuters

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.