"He was crucial from the last-16 onwards in every match and I think there's no doubt" that Benzema deserves to win the Ballon d'Or.
Messi was speaking a couple of days ahead of a friendly with Italy at Wembley stadium between two continental champions.
The match between the South American Copa America holders and the European champions, where many Argentines trace their roots, is known as the "Finalissima".
But while Argentina stormed to qualification for the Qatar World Cup later this year with several games to spare, Italy astonishingly missed out after losing to minnows North Macedonia in a play-off.
"What happened with Italy is crazy, having won the Euros and not being at the World Cup, given Italy's history at the World Cup," he said.
"If Italy had been at the World Cup they would have been one of the favorites. They were unlucky. No one would have wanted to play them."
Having spent his entire career at Barcelona, the 34-year-old moved to PSG a year ago where he has struggled to reproduce his best form.
He admitted it had been "a difficult change" and that the first day he took his children to school in Paris he left "crying".
Having caught Covid-19 at the end of 2021, Messi is convinced the virus has left "scars" in his lungs while he also admitted the Champions League capitulation against Real was "a tough blow".