Ronaldo Koeman, whose reign at Barcelona got off to a flyer against Villarreal last Sunday, showed faith with the same starting eleven that annihilated the Yellow Submarine.
Ansu Fati made it three goals in two games when he opened up his body on the edge of the area on 11 minutes to give Barca the lead with a one-touch finish past Celta goalkeeper Ivan Villar.
Celta pushed for a reply minutes after going behind, but a snap effort from the far side of the danger area by Jose Fontan was comfortably scooped by their opposite number Neto.
That was to be the fullback’s last contribution in the match as an earlier coming-together with Sergio Busquets cut short his evening on 32 minutes, with Nestor Araujo taking his spot in the side.
Barcelona's Clement Lenglet was sent for an early shower by the man in the middle three minutes before halftime after earning a second yellow card for a foul on Emre Mor, leaving the visitors on the back-foot.
This didn’t seem to bother the Catalans who returned for the second half with a two goal cushion on 51 minutes as a sliced of good fortune saw Lucas Olaza deflects Lionel Messi’s ball into his own net.
Barcelona threatened a third after four minutes when Fati combined with Messi who took the ball in his stride to race goal-wards before seeing his strike deflect into the side-netting.
The Catalan giants were pushed to the edge just after the midway period in the second half, with desperate defending in the area seeing Miguel Baeza’s effort come off the crossbar.
Barca put the contest to bed with the last kick of the game after Sergi Roberto volleyed into the top corner after Villar could only parry Messi’s shot, as the visitors maintain their winning start to the season.