Serena Williams has officially wrapped up her 2018 season.

The 23-time Grand Slam champion has withdrawn from the China Open in Beijing next week, which was set to be her final tournament of the year.

The decision to withdraw, though, likely has little to do with the ending to her controversial match at the U.S. Open earlier this month. This year marks the fourth-straight that the 37-year-old has declined to play in a tournament following the U.S. Open, making it almost a routine move for her at this point.

Williams has not played since her controversial match against Naomi Osaka in the U.S. Open Final earlier this month in New York. Williams fell to Osaka 6-2, 6-4, and was assessed three code of conduct violations in the match. Williams repeatedly argued with the umpire who assessed the penalties, and later said that they were unfair and only assessed because she is a woman.

Williams has won the China Open twice in her career — once at the inaugural event in 2004 and again in 2013. She has not competed there since 2014, when she reached the semifinals.

Williams, who is currently ranked No. 16 in the world, will likely take the court next at the Australian Open in January. She missed the event last year, declining to defend her 2017 title there shortly after giving birth to her child just months prior to the tournament.

She compiled a 18-6 record in 2018, reaching the final round at both the U.S. Open and at Wimbledon.

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