Raphinha and Lamine Yamal scored twice each as Barcelona returned to the top of La Liga with a convincing 5-2 victory over Rayo Vallecano at the Nou Camp.
Rayo, still searching for their first win of the season, stunned the home crowd when Sergio Camello put the visitors ahead after 12 minutes. Barcelona quickly responded, with Raphinha equalizing before Yamal put the hosts in front with 21 minutes played.
Florian Lejeune's own goal early in the second half gave Barcelona breathing room, but Camello struck again to keep Rayo within touching distance.
Raphinha restored Barcelona's two-goal advantage before Yamal completed his brace, securing a fourth consecutive victory and preserving the champions' perfect start to the campaign.
Rayo had arrived at the Nou Camp without a win in their opening two matches but showed little fear against their more illustrious opponents. They took the game to Barcelona early on and were rewarded when Camello fired into the bottom corner after Alvaro Garcia's well-weighted pullback.
It was the first goal Barcelona had conceded this season, but they responded immediately.
Raphinha drove a shot straight at Rayo goalkeeper Dani Cardenas, while Yamal also went close before the former broke into the box and fired into the bottom corner with 19 minutes gone.
Two minutes later, it was Yamal's turn to score and complete the turnaround for Barcelona. The World Cup winner cut into the box and fired his first goal of the season past Cardenas and into the top corner.
England winger Anthony Gordon was lively once again for the hosts and fired straight at Cardenas, who also had to tip over an effort from Marc Bernal as Barcelona continued to press.
The increasingly inevitable third goal arrived in unfortunate fashion for the visitors six minutes into the second half when Lejeune steered the ball into his own net. Barcelona's Jules Kounde also had an effort ruled out for offside.
But plucky Rayo were far from finished and gave Barcelona more to think about just before the hour mark when Camello flicked home from a Unai Lopez corner to narrow the deficit.
Gordon remained a major threat for the hosts and, after a number of missed chances, including a Fermin Lopez effort that was blocked in the box, the former Newcastle player created Barcelona's fourth with a neat backheel to Raphinha, who stroked the ball home.
Rayo continued to battle until the end, but Barcelona completed an ultimately comfortable victory when Yamal grabbed his second goal in the final minute, firing home from Karim Adeyemi's layoff.
