Naomi Osaka has been fined $15,000 for missing her first press conference at the French Open and threatened with being kicked out of the tournament if she continues to do so.
The World No.2 was sanctioned on Sunday after refusing to hold a press conference after her opening round 6-4, 7-6 (7/4) victory over Romanian World No.63 Patricia Maria Tig.
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The 23-year-old said before the tournament that she would refuse to carry out any media obligations, claiming news conferences are detrimental to her mental health.
She likened traditional post-match inquests to "kicking people when they're down".
"We have advised Naomi Osaka that should she continue to ignore her media obligations, she would be exposing herself to possible further code of conduct infringement consequences," said a statement from the four Grand Slam tournaments on Sunday after she was issued with the $15,000 fine.
"As might be expected, repeat violations attract tougher sanctions including default from the tournament and the trigger of a major offence investigation that could lead to more substantial fines and future Grand Slam suspensions."
French Tennis Federation president Gilles Moretton had previously described Osaka's vow of silence as "a phenomenal error" and "not acceptable".
The four Grand Slam events - the French Open, Wimbledon, Australian Open and US Open - said they had written to Osaka "to check on her well-being and offer support".
"She was also reminded of her obligations, the consequences of not meeting them and that rules should equally apply to all players," the statement added.
"Naomi Osaka today chose not to honour her contractual media obligations. The Roland Garros referee has therefore issued her a $15,000 fine."
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Following her win on Sunday, Osaka agreed only to an on-court TV interview.
"For me, playing on clay is a work in progress," said the reigning US and Australian Open champion.
"Hopefully the more I play, the better I will become."
Later on Sunday she tweeted: "Anger is a lack of understanding. Change makes people uncomfortable."
The Grand Slam Board said Osaka's refusal to take part in media duties put opponents at a disadvantage.
"There is nothing more important than ensuring no player has an unfair advantage over another, which unfortunately is the case in this situation if one player refuses to dedicate time to participate in media commitments while the others all honour their commitments," they said.
If Osaka was to be disqualified, it would be as sensational as Novak Djokovic's default at last year's US Open where the World No.1 was booted out for hitting a line judge with a ball.
Osaka's stance on press conferences has heavily divided the tennis world.
"For me personally, I was always trying to follow the rules and be fair not only on the court but off the court as well," said two-time Wimbledon champion Petra Kvitova after her opening win.
"Now it's up to them to decide what's going to be."
Osaka's compatriot Kei Nishikori added: "It's not good but I understand her situation. So it's good and bad."
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