The 10th-seeded Cibulkova fell 6-2, 5-7, 6-2 to unseeded Alize Cornet in the second round in Beijing. Carolina Wozniacki continued her late-season charge, dominating No. 13 seed Roberta Vinci 6-3, 6-2 and setting up a third match against Radwanska in as many weeks. Wozniacki beat Radwanska in Tokyo, with Radwanska returning the favor in Wuhan last week.
No. 4 Simona Halep, No. 9 Svetlana Kuznetsova and No. 14 Petra Kvitova all advanced in straight sets, while American qualifier Alison Riske was a 6-3, 4-6, 7-6 (4) loser to Shuai Zhang in a match that lasted two and a half hours. Kvitova, who is coming off a title at Wuhan, beat China's 6-4, 6-1, and will next face Garbine Muguruza as she attempts to make a late charge for a WTA Finals spot of her own.
"I was pretty tired. I had two days off, which I think helped me. For sure, was a good win today. We'll see how everything is going, like, in the next days," Kvitova said.
"But I think I still do have motivation. I think it was a great week in Wuhan. I think that gave me more motivation and confidence, which I really needed before. I'm not really struggling with motivation here."
Angelique Kerber, Serena Williams and Simona Halep have also secured spots, although Williams' availability remains uncertain as she recovers from a shoulder injury that has sidelined her since losing to Pliskova at the U.S. Open. The final three spots are currently held by Muguruza, Cibulkova and Carla Suarez Navarro, with the results of the China Open determining the eight-player field. American Madison Keys, who has advanced to the second round in Beijing, currently sits in ninth place, followed by Great Britain's Johanna Konta.
"I'm very excited that I have qualified for the WTA Finals in Singapore," said Pliskova. "It's been an amazing year so far and the best is coming at the WTA Finals. I hope to see many fans in Singapore and that many more follow my matches from around the world. Wish me luck - I am excited to be there for the first time in my life."