World number eight Sloane Stephens has qualified for the season-ending WTA Finals for the first time.
The 25-year-old American, who won the US Open last year, is 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 said she will not play an event this week.
Svitolina, Karolina Pliskova and Kiki Bertens are vying for the final two places in the event.
Both Pliskova and Bertens are playing at this week’s Kremlin Cup in Moscow.
World number one Simona Halep, Wimbledon champion Angelique Kerber, US Open winner Naomi Osaka, Petra Kvitova and Australian Open champion Caroline Wozniacki have already qualified for the Finals.
Garcia takes Tianjin Open title
Meanwhile, Caroline Garcia won her first title of the year by beating Pliskova to edge a nervy Tianjin Open final in China on Sunday.
The Frenchwoman 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.