Melbourne ¨C Tennis greats Martina Navratilova and Lindsay Davenport took Naomi Osaka to task on Friday, saying she had failed to keep to ¡°basic etiquette¡± after her Australian Open flashpoint.

The Japanese star¡¯s second-round win against Sorana Cirstea was marred by a testy exchange and icy handshake at the end.

Veteran Cirstea, in her 18th and last visit to Melbourne Park before retiring, took issue with Osaka shouting ¡°come on¡± between the Romanian¡¯s first and second serves.

During her on-court interview, two-time Australian Open winner Osaka was dismissive of Cirstea, but later apologized for being ¡°disrespectful.¡±

¡°I can get what (Osaka) said after the match because it¡¯s kind of in the heat of the moment ¡ª she was surprised by Cirstea¡¯s reaction at the handshake,¡± 59-time Grand Slam champion (in singles, doubles and mixed doubles) Navratilova said on the Tennis Channel.

¡°But you cannot be talking out loud between first and second serves of your opponent.

¡°Cirstea was ready to hit the second serve and Osaka said c¡¯mon ¡ª that¡¯s not right. I don¡¯t think she does it on purpose, she doesn¡¯t realize it.

¡°You can say c¡¯mon all you want, but keep it inside, do not verbalize it.¡±

Davenport, the 2000 Australian Open champion, said she did not expect Osaka to do it again in her third-round match against Australian qualifier Maddison Inglis.

¡°Osaka¡¯s 28 years of age, she¡¯s played tennis for a long time, it¡¯s just something you don¡¯t really do,¡± Davenport said on the same program.

¡°We all know Osaka doesn¡¯t have a mean bone in her body, so I would be surprised if she continued with that behavior.

¡°You can pump yourself by hitting your thigh (but) you can¡¯t yell out in between serves. Basic tennis etiquette 101.¡±

Cirstea was keen to play down the controversy in her postmatch news conference, insisting there was ¡°no drama.¡±

¡°It was just a five-second exchange between two players that have been on tour for a long time. It stays between us,¡± she said.