A Russian Premier League referee has denied claims by Zenit striker Hulk that he racially targeted the Brazilian during Saturday's match.
Hulk told Reuters Brazil that he touched referee Alexei Matyunin as they calmly discussed a game incident in the second half, and the referee said not to touch him.
Hulk says the referee told him: "I don't like you, along with any other black people."
Matyunin denied the claims, saying he was shocked that Hulk would say such a thing, and that he was prepared to defend himself through legal action.
"I can't comment on someone's fictionalised version of events, or someone's stupidity, but it is clear that this resembles some kind of game," he was quoted as saying in Sport Express. "It's like kindergarten, but with angry, stupid kids. It looks like someone has planned this to manipulate things. Somebody has advised someone to do this -- someone with some kind of apparent interest in this happening.
"I don't believe Hulk could say something like that, since we both know that it didn't happen, and there are witnesses from both teams.
"A charge of racism is very serious. It is a criminal offence -- and you have to have serious grounds for the accusation, and evidence for it. I want to say that delibate slander is also a crime. To prove it will not be difficult. We will now check to see who is the source of the libel. After that, a lawsuit will not take long. But I repeat: this is like a game that has absolutely nothing to do with football. It is someone's mean and dirty game."
In 2011, Matyunin was suspended for a year for statements supposedly directed toward Dagestan native Albert Gadzhibekov, but the ruling was later reversed on appeal.
"Someone already tried to spark a scandal like this before, but I defended my good name and honour," he said. "I want to say: Do not make the same mistake again, because you will be hurt."
In October, Hulk said he was the target or racist chants from Spartak Moscow fans, but he told Reuters he expected a different reaction from the referee.
"You can always expect some kind of racist chants from the fans," Hulk said. "This is unacceptable, of course, but it is clear that fans use this tactic to infuriate the opposition's players. But a referee cannot be involved in these types of scandals."
League leaders Zenit lost 1-0 away to Mordovia Saransk on Saturday.