World number eight Sloane Stephens has qualified for the season-ending WTA Finals for the first time.
The 25-year-old American became the sixth player to qualify for the event in Singapore, which begins on 22 October.
Her place was confirmed after world number five Elina Svitolina confirmed she will not play an event this week.
The final two spots will be taken by either Svitolina, Karolina Pliskova or Kiki Bertens.
Already qualified are world number one Simona Halep, Wimbledon champion Angelique Kerber, US Open winner Naomi Osaka, Petra Kvitova and Australian Open champion Caroline Wozniacki.
The last two positions will be decided at this week’s Kremlin Cup in Moscow where both Pliskova and Bertens are playing.
Garcia takes Tianjin Open title
Meanwhile, Caroline Garcia won her first title of the year as the French player defeated Pliskova to edge a nervy Tianjin Open final in China on Sunday.
She battled through a narrow first set before defeating the Czech top seed 7-6 (9-7) 6-3 for the sixth title of her career.