By the brilliant Argentine's standards, he was in a goal drought after failing to net for his new club since his move from Barcelona, even if his appearances had been limited by injury.
But in the 74th minute of his reunion with Manchester City's former Barca boss Pep Guardiola, Messi finally delivered.
It was a trademark strike by the Argentine that put PSG 2-0 up against Guardiola's side, securing a victory that sends out a message to the rest of Europe, even this early in the season.
The six-time Ballon d'Or winner was having a quiet evening until he collected possession just inside the City half near the right touchline and accelerated towards goal.
He held off Aymeric Laporte and played a one-two with Kylian Mbappe before sending a shot high into the net from just outside the box.
Guardiola - who has been on the receiving end of Messi's magic before against Barcelona with Bayern Munich and with City - called his former pupil "unstoppable".
"I don't usually celebrate goals, but that one I did," said PSG coach Mauricio Pochettino.
"I have seen him score plenty of times before when I was on the opposition bench, so for once I was on the right bench and could celebrate."
The goal certainly meant a lot to Messi, as can be seen in the picture gallery above.