Robert Lewandowski scored his fifth goal in three LaLiga games and Raphinha opened his Barcelona account in a 3-0 victory over fragile Sevilla.
Raphinha opened the scoring with a simple header and Lewandowski capitalised on Sevilla's defensive frailties to double Barca's lead in the first half.
Eric Garcia got in on the act with his first senior goal in the second half and Jules Kounde provided two assists against his former club on his return to the Ramon Sanchez-Pizjuan, where Barca cruised to a third consecutive victory.
Angry Sevilla fans turned voiced their disapproval during a defeat that leaves them with just one point from four matches.
Sevilla made a promising start and Marc-Andre ter Stegen produced an excellent one-handed save to deny Ivan Rakitic when the former Barca midfielder went one-on-one with the goalkeeper after some slack defending.
The Blaugrana sparked into life and produced a devastating counter-attack to take the lead after 21 minutes, with Fernando clearing off the line after Lewandowski dinked the ball over Yassine Bounou but only onto the head of Raphinha, who could not miss from point-blank range.
Lewandowski made Los Rojiblancos pay for leaving him unmarked nine minutes before the break, taking a pinpoint pass from Kounde on his chest and volleying inside the bottom-left corner with his right foot.
Kounde somehow failed to add a third against his former club when he headed wide unchallenged from only five yards out with Sevilla all at sea at the back.
Defender Kounde turned provider for a second time early in the second half, heading Raphinha's delivery from the right across goal unmarked to give Garcia a tap-in.
Bounou showed sharp reflexes to keep out another Lewandowski volley after Sergi Roberto picked the striker out with a whipped cross from the right.
Lewandowski failed to chip Bounou when he was sent clear again as the busy keeper stood tall and stuck out a palm and Frenkie de Jong was unable to finish following up on a painful evening for Julen Lopetegui's struggling side.
What does it mean? Free-scoring Barca on a roll, Sevilla fans fuming
That is 11 goals in three LaLiga games for a new-look Barca side that were a joy to watch going forward and they really should have put Sevilla to the sword as they moved into second place.
Although it is so early in the season, Los Rojiblancos fans are right to be concerned following a third defeat in four matches and they made their feelings crystal clear when the final whistle sounded.
They have won just one of their 31 LaLiga matches against Barca since the start of the 2007-08 season and there were inexplicably huge gaps at the heart of their defence as they were opened up time and again.
Dream start for ruthless Lewandowski
Lewandowski has made a dream start to life at Barca and showed his class in front of goal yet again with a brilliant first-half finish.
The Poland captain became only the third player to score five or more goals in his first four LaLiga games, a feat also achieved by Cristiano Ronaldo in 2009 and Radamel Falcao 11 years ago.
Kounde rubs salt in the wounds
France international Kounde was not signed by the Blaugrana for his creativity, but he showed that side of his game as he returned to haunt his former employers.
In his 97th LaLiga appearance, this was the first time he has provided two assists. He also become the first Barca player to lay on two goals in his first league away game in the 21st century.
Barca host Viktoria Plzen in the Champions League on Wednesday before travelling to Cadiz on Saturday. Sevilla start their Champions League campaign with a home clash against Manchester City on Tuesday before returning to league action at Espanyol four days later.