Melbourne –

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.