Lionel Messi and Luis Suarez both scored twice as Barcelona hit eight goals past La Liga newcomers Huesca.
The minnows took an early lead through Watford loanee Cucho Hernandez but Messi levelled with a shot off the post.
The Argentine also hit the bar and added a second on the counter-attack, as well as assisting two goals.
He could have had a hat-trick when Barca won a late penalty, but he let Suarez take it for his second goal.
The win takes Barcelona level with Real Madrid at the top of La Liga on nine points from three games.
Huesca – in their first top-flight season – lost 8-1 on their only previous trip to the Nou Camp in the Copa del Rey in 2014-15.
They got off to a perfect start when 19-year-old Hernandez turned the ball home from close range.
Messi levelled with a good finish after skilfully moving into the box.
The champions took the lead when Jorge Pulido scored an own goal from Jordi Alba’s cross, and the Barca defender then set up Suarez for a goal eventually allowed by the video assistant referee.
Alex Gallar gave the visitors, who had not lost in their opening two games, renewed home with a close-range goal moments later.
But Barca were rampant after the break with Ousmane Dembele scoring his third goal of the season from Suarez’s pass.
Messi then set up a great goal, with Ivan Rakitic smashing the ball home on the bounce.
The Argentine chased on to a Philippe Coutinho ball to score his second, then played in Alba for Barca’s seventh – in the week the left-back was left out of Spain’s squad.
Suarez won an injury-time penalty following a foul by keeper Axel Werner and threw the ball to Messi so he could score his third. But the Barcelona captain gave the ball back to his team-mate, who sent Werner the wrong way.