Rio de Janeiro - Neymar was branded a "coward" and "adolescent" by Brazilian media Monday after the superstar struck a fan who had insulted Paris Saint-Germain players following their French Cup final defeat.
PSG lost 6-5 on penalties after a dramatic game finished 2-2 at the end of extra time on Saturday at the Stade de France.
Numerous cell phones caught the moment that Neymar, the world's most expensive footballer, hit a fan in the face after he had taunted some of the players as they went to receive their medals.
The incident came days after Neymar was suspended for three Champions League matches by UEFA for a foul-mouthed tirade at match officials following PSG's shock exit from this season's tournament to Manchester United.
Neymar later admitted he had made a mistake hitting the fan, writing on Instagram: "Did I act badly? Yes. But no one can stay indifferent."
Brazilian sports commentators disagreed.
"As if his endless failures, his lack of education, antipathy and superficiality were not enough, Neymar has now shown himself to be a coward," Juca Kfouri wrote in the influential daily Folha of Sao Paulo.
"For all his talent, Neymar will never be equal to Lionel Messi or Cristiano Ronaldo. If he is happy that way, let him enjoy it."
Another columnist for the same newspaper, Mathias Alencastro, said Neymar had turned into a "rebellious adolescent."
Neymar "appears incapable of dealing with criticism, of dealing with frustrations," wrote Marcelo Tieppo for the news site Terra.
"It might be comfortable for the Brazilian to continue in this fantasy world, but it would be better if the striker started to live in reality."
The victim of the blow, named only as Edouard, a 28-year-old delivery driver from Nantes, denied he had insulted Neymar.
"I told him that they had been useless," Edouard told French sports daily L'Equipe.
"When the players passed, Verratti, Buffon, I mocked them: 'You are worthless. Allez Rennes!'"