Messi admitted his latest Ballon d'Or win was largely down to leading his country to a major international title for the first time in the Copa America, although he did also finish as La Liga top-scorer last season in a weak Barcelona team which has since stumbled from crisis to crisis.
After scoring just four goals in 11 appearances this term for PSG, the 34-year-old will need an upturn in fortunes to be named the world's best player again next year.
Liverpool manager Jurgen Klopp was among the leading football figures to express surprise that Messi beat Bayern Munich striker Robert Lewandowski to the prize.
But PSG coach Mauricio Pochettino was in no doubt that his player deserved to become the first from the French side to win the Ballon d'Or, despite failing to fully fire for the capital club.
"He totally deserves the Ballon d'Or. There is no debate on this subject," Pochettino insisted ahead of PSG's game against high-flying Nice on Wednesday.
"I can understand that in other countries some do not agree, but I think he deserved it.
"We also hope that it is the first day of the makings of what can become an eighth Ballon d'Or. We are all delighted to have Messi here."
Messi, along with midfielder Leandro Paredes, did not train on Tuesday due to illness, but he will want to be fit to face third-placed Nice, especially with Neymar sidelined for up to eight weeks by an ankle injury.
PSG are already 12 points clear of second-placed Rennes in the French top flight, despite a series of underwhelming performances this season after a raft of high-profile signings.
Messi, Neymar and Kylian Mbappe have scored only 11 times in 31 league appearances between them.
They will need to improve to make a mark in the Champions League, where they had to settle for second in their group behind Manchester City.
Nice, bankrolled by British billionaire Jim Ratcliffe's Ineos, will be no pushovers this week though, despite a shock home loss to lowly Metz last weekend.