US Open champion Naomi Osaka has qualified for the WTA Finals in Singapore for the first time.
The 20-year-old Japanese player becomes the third woman to book her place at the season-ending event later this month, joining world No.1 Simona Halep and Wimbledon champion Angelique Kerber.
The remaining five players will be confirmed over the last three weeks of the regular season, with the WTA Finals beginning on October 21.
Osaka established herself as a contender for the big titles by winning in Indian Wells in March and then produced a stunning run in New York, culminating in a dramatic victory over Serena Williams to win her maiden slam title.
Osaka's achievement, becoming the first Japanese player to win a slam singles title, was overshadowed by the row between Williams and umpire Carlos Ramos, and the 20-year-old told media at the China Open that the memory feels "bittersweet".
Halep's participation has been thrown into doubt after a scan revealed she had suffered a herniated disc in her back.
French Open champion Halep was injured while training at last week's Wuhan Open, where she lost in the second round to Slovakia's Dominika Cibulkova.
Romanian Halep aggravated the problem during her China Open first-round match on Sunday against Ons Jabeur and was forced to retire after losing the first set.
"I had an MRI on my back and found out I have a disc hernia," Halep said on Twitter.
"I will discuss with doctors in the next few days but hope to be back soon and will keep you updated."
Halep, who won her maiden Grand Slam trophy in Paris this year, became the first player to qualify for the season-ending WTA Finals in Singapore from Oct. 21-28.