New York: Tennis legend and 18-time Grand Slam singles champion Martina Navratilova has come down hard on Serena Williams, saying that screaming at the umpire is wrong no matter if it is done by a man or a woman. Navratilova, however, agreed there is a double standard.

Sixty-one-year-old Czech-American Navratilova was talking about Serena Williams' outburst against the chair umpire Carlos Ramos, calling him a thief and asking him to apologise. Serena was penalised a key game in the second set.

"Serena Williams has part of it right. There is a huge double standard for women when it comes to how bad behaviour is punished and not just in tennis," Agence France-Presse quoted Navratilova as saying.

"But in her protests, she also got part of it wrong. I don't believe it's a good idea to apply a standard of, 'If men can get away with it, women should be able to, too,'" she further said.

Williams's coach Patrick Mouratoglou accepted to coaching her from the stands, the reason why Williams was warned.

Williams, furious over being warned, smashed her racquet, resulting in a code violation and a point deduction.

"She was insisting that she doesn't cheat, completely believable, but besides the point, while he was making a call over which he, at that point, had little discretion," Navratilova further said.