During the final against Osaka, Williams got a warning for violating a rarely enforced rule against receiving coaching from the sidelines. "In a situation where we know Serena is unbelievable; she's iconic; and we know that Carlos is there because he's worthy of being there for those matches".
"I guess I'd like to hang out with my sister - I haven't seen her since Wimbledon", said Osaka, who has become an unlikely hero in a country still reeling after a summer of deadly typhoons and earthquakes.
"It's not something that I have to think about".
Tennis icon Billie Jean King has said she also believes tennis applies a double standard to women compared with men, and a similar outburst by a male player would have drawn no repercussions.
The Japanese player's breakthrough triumph in NY was overshadowed by an explosive row between her opponent Williams and umpire Carlos Ramos which resulted in the 23-times Grand Slam champion being docked a game and fined $17,000. For me to say "thief" and for him to take a game, it made me feel like it was a sexist remark. The WTA defense surprised me.
In US Open championships featuring the 23-Grand Slam victor, viewership has been nearly double that reported for the men's final.
Speaking on Wednesday, Osaka said she was unsure just why the crowd were booing at the time, but Williams had some kind words for the champion. How many other men do things?
The International Tennis Federation released a statement in support of Ramos.
In an opinion piece for the New York Times, Navratilova, 61, wrote: "We can not measure ourselves by what we think we should also be able to get away with". In fact, this is the sort of behavior that no one should be engaging in on the court ...
"I think the umpire did what was within his rights", he told BBC Sport ahead of Britain's Davis Cup tie with Uzbekistan in Glasgow.