American great Serena Williams was left out of the China Open tennis draw on Friday as she appeared to call time on her season following her meltdown at the U.S. Open. Williams' name, along with that of her sister Venus, did not appear on a list of 64 players ahead of the start of the tournament in Beijing, one of the women's tour's mandatory events.

It comes less than three weeks after the tempestuous U.S. Open final, where Williams, 37, accused the umpire of lying and sexism in an angry rant during her 6-2, 6-4 defeat to Japan's Naomi Osaka. In extraordinary scenes, Williams went into a tailspin after a warning for receiving coaching from the sidelines, smashing her racket and being docked a point and then a game. The 23-time Grand Slam singles champion later said she wanted to "move on" from the incident, but maintained that women players could not get away with "even half of what a guy can do."

"Right now we are not, as it's proven, in that same position," she told Australia's Channel Ten.

"But that's neither here nor there. I'm just trying most of all to recover from that and move on." The episode polarized tennis with many expressing sympathy for Williams, while others said her behavior was out of line. Reports from the United States said Williams' season is now over, which would make it the fourth year in a row she has curtailed her playing commitments – although in 2017 she took time off to have a baby. The biggest event left on the 2018 calendar is next month's elite, eight-player WTA Finals in Singapore. Williams is currently 11th on the Race to Singapore rankings.