Billie Jean King says Serena Williams was "totally out of line" for her outburst in the US Open final, but also believes umpire Carlos Ramos "blew it".
Williams, beaten in straight sets by Naomi Osaka, was docked a game for verbal abuse, having already had a point penalty for smashing her racquet and a code violation for coaching.
The American later said it was "sexist" to have been penalised a game.
"Serena was out of line, there's no question," said legend King.
American King, one of the founders of the Women's Tennis Association (WTA), initially backed the 23-time Grand Slam champion, saying in the aftermath of Saturday's final: "When a woman is emotional, she's 'hysterical' and she's penalised for it.