A hard challenge from opponent Rodrigo Nestor sparked the incident during Santos' match. Neymar took exception to Nestor's unnecessary challenge and threw the ball at him, earning a yellow card just over half an hour in.
Amid a heated argument with Nestor, Neymar confronted Bahia coach Rogerio Ceni and pushed him. Shortly before the second half began, tempers had still not cooled, and Neymar fell foul of the so-called Vinicius Junior rule.
Since the incident involving Gianluca Prestianni in the Champions League clash against Vini Jr., in which the Benfica star is alleged to have racially abused the Real player while covering his mouth, FIFA have introduced a rule under which a player who covers his mouth can be sent off.
The rule applies not only at the World Cup but also in the Brazilian league. Nestor alerted the referee after Neymar covered his mouth while arguing with him. A brief VAR review followed, and Neymar was sent off.
After the dismissal, Neymar tried to go after Nestor and was only just held back. The 34-year-old apologised to Santos fans after the match, but made serious accusations against Nestor on Instagram.
What did Neymer say about the clash with Nestor and his red card?
"What Nestor did to me today is a very serious matter. This rule was introduced to combat racism, and he wanted to gain an advantage in the match because I put my hand over my mouth: I didn't say a word to him," he fumed.
Neymar admitted trading insults, which he said was normal in football. "But what he did is very serious. If it's a rule against racism, how can he do something like that? It's surreal. I'm sad about what happened. He was really very underhand, to be honest."
After Nestor gave an interview about the incidents following the match, Neymar mocked him. "What kind of role model does he want to be? He talked about decency. I'm decent too, but I'm a man: you simply don't do what you did," he complained.
"I gave an idiot the chance to show himself. Thank you, Nestor. I'll be able to sleep soundly, but you, with your underhand games: you won't be able to," he concluded.