Rodrygo featured as Fede Valverde and Kylian Mbappe struck in the 2-0 win.
He said, "I'm very happy. It was what we wanted, to start the season like this, with a title, like we finished the last one. It gives us a lot of confidence for the rest of the season, which is going to be very long.
"We haven't trained very much, but we were ready to deliver as quickly as possible. We're improving and we're going to do much better for the rest of the season. In the first half the pitch was a bit dry. In the second half, when it was wet, it was a different game. We'll keep training to improve, because it's a pleasure to be at this club."
On Mbappé, he added: "It's the same as with Vini and Jude. Now another player has joined us, one of the best in the world. The coach asks us to change positions a lot and not to stand still."