La Liga - Messi plays down 'assault'
"I wasn't even touched," Messi said after a punch thrown by a youth wearing a hoodie failed to make contact.
"I didn't feel a thing and I only found out after all the kerfuffle, it was nothing," Messi told sports daily Ole from Rosario, 300 km north of Buenos Aires.
Messi, on holiday after another brilliant season in which he helped Barcelona win the Champions League, left the restaurant with friends and was surrounded by autograph hunters.
Argentine media, who gave the incident massive coverage, said Messi's aggressor was a fan of Rosario Central, arch-rivals of Newell's Old Boys where the 23-year-old spent his formative years before joining Barcelona some 10 years ago.
"We're taking photos and we see the arm and he dodges it. (Messi) did not react badly, he left walking and got into the (car)," witness Carolina told the TV news channel C5N.
Messi will report to national team coach Sergio Batista on June 8 to begin training for next month's Copa America hosted by Argentina.