PSG defeated the English champions and the competition’s beaten finalists last season 2-0 at the Parc des Princes.
The six-time Ballon d’or winner, making his fourth appearance for Mauricio Pochettino’s men after joining from Barcelona last month, combined well with Kylian Mbappe in the 74th minute to strike past Ederson in the Man City goal, adding to Iddrisa Gana Gueye’s early opener to give PSG victory.
The win takes PSG top of Group A on four points, having drawn their first game away at Club Brugge.
"It was a perfect night against a great opponent," Messi told Canal+. "For us, it was very important to win this game after Brugge (a 1-1 draw away).
"I am very happy to have scored. I haven't played much recently, I had only played one game here. I am adapting little by little. What is important is to keep winning.
"Our relationship will get better and better with each game. We all have to grow together, increase our level of play. We have to continue.
"We won a very important game against a very big rival, who was in the final last year. We must continue to progress, improve a lot of things for the future."
Messi has now scored 121 times in the Champions League, with 27 of those coming against English opposition.
