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PARIS -- Paris Saint-Germain's Lionel Messi era is well and truly underway now after the legendary Argentine continued his habit of scoring against Manchester City in a 2-0 win for the French giants on Tuesday which suddenly gives them a foothold in UEFA Champions League Group A.

Moreover, the result is huge for head coach Mauricio Pochettino who was under intense scrutiny pre-match due to a lack of clear identity but has now delivered a result to match an impressive start to the season on paper thanks to Messi, his illustrious compatriot, and Idrissa Gueye.

Gianluigi Donnarumma deserves recognition for an assured Champions League debut with a string of saves to keep Pep Guardiola's visitors at bay, and although City will struggle to live down Bernardo Silva's incredible miss, the Italian Euro champion did not look out of his depth at Parc des Princes.

"People were talking on social media about me leaving PSG because of Keylor playing as starter," Donnarumma said post-match. "I was laughing looking at social media. It is full of fake news. I am totally happy to be at PSG, so let them talk -- the club is supporting me.'

However, the main talking point was Messi and the fact that he has opened his PSG account with a classic finish to double Les Parisiens' advantage after they were forced to ride a wave of City pressure after the restart.

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Messi drifted in and out of the game and only occasionally linked up with his fellow attackers Neymar and Kylian Mbappe before the goal. But when it came, the build-up featuring Marco Verratti and the Frenchman was as sublime as finish from the new No. 30.

"I celebrated today," said Pochettino post-game. "I do not usually celebrate goals -- it is internalized. Today, though, I let out a shout. I have spent long enough seeing so many Messi goals against me. I had to celebrate the one for me."

"If Leo is happy in Paris, I will be so happy for him," added beaten City boss Guardiola after the final whistle. "Let me also say that I am in love with Verratti. He is an exceptional player. He is small but you can always count on him. I am happy he is back from injury."

Pochettino might have been tempted to withdraw Messi before the goal as it certainly felt like he had little more to offer after a draining return to action after missing the previous wins over Metz and Montpellier in Ligue 1 due to a knee issue.

The former Tottenham Hotspur boss' decision to stick by his fellow Argentine paid off greatly, though, and was ultimately the difference between scraping a win and boasting the final score to match what was an accomplished performance across the board.

"I really wanted to get out there," admitted Messi. "I have not played much. I am still getting used to my teammates and to the team. Today was an important moment for me."

For the second consecutive outing, PSG kept a clean sheet, and the midfield continues to grow in influence under Pochettino with Gueye scoring in back-to-back matches to complete a prolific September.

Of major importance for PSG now is to not get carried away and assume that the hardest part has been done -- results and performances will not automatically come because of this and it remains a pressing issue to identify the strongest XI and style to match as the season wears on.

What this does do in an immediate sense is it undoes the damage of an opening draw away at Club Brugge and puts PSG's Group A fate back in their own hands thanks to the Belgians' impressive victory on the road at RB Leipzig, who come to the French capital next.

The touchpaper on the French giants' season has now been lit and it is up to Pochettino, Messi and this star-studded team to keep building on early results with an unbeaten league campaign a definite possibility and top spot in Champions League Group A suddenly looking more attainable.