Messi, who recently announced that he would be staying at Barcelona, has been given a 93 rating, while Juventus talisman Ronaldo, whose team is known as Piemonte Calcio in the game for licensing reason, has a 92 rating.
Elsewhere in the Premier League, Sergio Aguero keeps the 89 rating he had in FIFA 20, while Harry Kane and N'Golo Kante have seen their ratings fall by one point to an 88.
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City pair Raheem Sterling and Ederson are also rated 88, the same as last year's game.
Some players have already spoken about their ratings, with Romelu Lukaku writing on Twitter: "Let’s be honest fifa just mess with the ratings so we players start complaining about the game and give them more publicity... i ain’t with this sh*t. I know what i do"
Lukaku's rating has remained at 85.
Arsenal skipper Pierre-Emerick Aubameyang was left baffled after his rating was downgraded from an 88 to an 87, despite matching last season's haul of 22 league goals.
Responding to a post from Arsenal Fan TV with a picture of Aubameyang's rating, the striker simply used laughing face emojis.
Meanwhile, Premier League Young player of the Year Trent Alexander-Arnold was shown his new rating on BBC Football Focus and immediately responded: "Yeah I'm happy, of course! 87. Wow, thats high!"