Barcelona kicked off their La Liga title defence against Alaves at Camp Nou.
The Catalan side starting well, winning back the ball from the kick-off almost immediately, and enjoying a long period of possession.
Messi was high, chasing down defenders, which initially looked like it was making Agirregabiria and Laguardia nervous.
However, despite and because of the high press Barcelona were sporting, Alaves were able to mount a number of counter attacks.
Unfortunately for Alaves, Barcelona were still able to create some attacking chances themselves.
Suarez was the main man with the chances, going close after a Dembele link up, and then again when a looping through ball allowed him to attempt a dink over the keeper.
Messi also came close to opening the scoring, after Garcia conceded a free-kick on the edge of the Alaves box.
The new Barcelona captain stepped up to take, and his shot was inches away, bouncing down off the crossbar before being quickly headed away.
Alaves didn't have a bad first half, and managed to keep Barcelona at bay, but they didn't have many chances of their own, and had some luck defensively.
Coutinho's addition at the start of the second half, and the substitution of Semedo showed that Barcelona meant business.
The home side started the second period well, and again enjoyed the majority of possession.
Jordi Alba was through on goal, but was denied by Pacheco at close range.
Barcelona were getting frustrated, but were awarded a golden opportunity in minute 64.
Messi received a stamp while dancing through defenders on the edge of the box, and stepped up once more to try and break the deadlock.
This time, Messi didn't miss. His ball curled under the wall, flying into the bottom corner.
August 18, 2018
The goal is Barcelona's 6000th, and also marks 15 consecutive seasons of Messi scoring in La Liga.
The goal spurred Barcelona on, and Messi went close a few minutes later, his shot coming off the post and away.
Coutinho doubled Barcelona's lead in minute 83, whipping a shot past the keeper.
August 18, 2018
From then on, Barcelona looked totally dominant, and Alaves looked tired.
Messi struck again in extra time, latching onto a lob ball and bringing it down to slot into the left hand corner.
Barcelona's pressure was relentless, and despite a less exiting first half, they were still able to pull it out the bag in order to grab their first three points of a new La Liga campaign.