Billie Jean King says there's a double standard in tennis when it comes to rules applied to women compared to men.

Serena Williams was penalized a game for calling the chair umpire a thief during an extended argument as the U.S. Open women's final. Williams clashed with chair umpire Carlos Ramos, demanding an apology after he initially issued a warning for a code violation in the second set's second game for receiving coaching, which is not allowed during Grand Slam matches.

King tweeted, "when a woman is emotional, she's 'hysterical' and she's penalized for it ." King wrote that if a male player had a similar outburst, he'd be called "outspoken" and have no repercussions.

King also tweeted that coaching should be allowed in tennis .

 

The USTA says the decision by the chair umpire to hit Serena Williams with code violations is final and the actions were not reviewable.

Williams received a warning from umpire Carlos Ramos for receiving coaching; was assessed a second code violation for racket abuse, which required a point penalty; and got hit with a third code violation for verbal abuse in the judgment of the umpire, which then required a game penalty.

Williams called Ramos a thief during an extended argument in women's final.

The WTA says it will look into the dispute between Williams and Ramos.

Naomi Osaka went on to defeat Williams 6-2, 6-4 to win the U.S. Open and become the first Grand Slam champion from Japan.