Robert Lewandowski gave FC Barcelona three points at the start of La Liga against Valencia.
The team of new manager Hansi Flick won 2-1 away to Valencia, with Lewandowski scoring both goals.
Barcelona, where Frenkie de Jong was still not available after recovering from an injury and with three 17-year-olds in Lamine Yamal, Pau Cubarsí and Marc Bernal in the starting line-up, conceded a goal in the 44th minute at Mestalla.
Hugo Duro scored on an assist from Diego López 1-0. Pau Cubarsí prevented Duro from scoring a second goal.
The defender was just able to stop the effort of the Valencia striker before the goal line.
Barça seemed to be heading for the dressing room with a deficit, but it was Robert Lewandowski who put his foot to a cross from Lamine Yamal: 1-1.
Shortly after the break, Barcelona were awarded a penalty after a foul by Cristhian Mosquera on Raphinha.
Lewandowski stepped up to the ball and made no mistake from the penalty spot.
Deep into injury time, Lewandowski missed a big chance to complete his hat-trick, but Barça took the points from Valencia on the official debut of German coach Hansi Flick.
