Her stance was swiftly backed by the WTA Tour's chief executive Steve Simon, and USA great Billie-Jean King, both of whom also questioned the initial code violation handed to Williams for on-court coaching. Osaka's decpition as having blonde hair despite her Haitian and Japanese heritage was also called out, although the player does sport blonde highlights in her natural dark curls.
Naomi Osaka - a self-confessed Serena fan - went on to win her maiden grand slam amid unsavoury scenes where she was jeered during the presentation ceremony and felt the need to apologise to the unhappy fans on Arthur Ashe court.
In an even more extreme case, cartoonist Rob Rogers was sacked from the Pitsburgh Post-Gazette earlier this year because his drawings were too critical of President Donald Trump.
Knight responded to the criticism by pointing out that he had drawn an unflattering portrayal of Australian male tennis star Nick Kyrgios "behaving badly".
"Yesterday brought to the forefront the question of whether different standards are applied to men and women in the officiating of matches", Simon said on Sunday.
Croatia - UEFA Nations League - 11 September 2018
His first goal was emphatic and he deserved his second effort to go straight in, rather than deflect off the back of the keeper.
Williams, a six-time US Open champion, has since been fined $17,000 by the United States Tennis Association for the violations.
Writing in an opinion article for the New York Times, the 61-year-old Czech-born American said a higher standard needed to be observed when Williams called chair umpire Carlos Ramos a "thief" and was penalized a key game in the second set. "In fact, this is the sort of behaviour that no one should be engaging in on the court".
Novak Djokovic screamed at Ramos during the 2018 Wimbledon tournament, threw his racket, and even pretended to throw the ball at the umpire, but never lost a point or a game.
In the absence of any official support for Ramos until Monday, it was left to two former senior umpires, Mike Morrissey and Richard Ings, to publicly defend the Portuguese official. "It is the inconsistency", said Azarenka in a live video on her Instagram page. "There's no equality when it comes to what the men are doing to the chair umpires and what the women are doing, and I think there has to be some consistency across the board". "Whether you agree with the umpire or not, I don't think sexism played a role in that".
Belarusian player Victoria Azarenka, commenting on the coaching issue, said it bothers her to have inconsistent rules.
King, however, said Williams was not aware she had been handed a first violation and was surprised to have a point taken from her when she received a second for later smashing her racquet.