Agnieszka Radwanska and Karolina Pliskova booked their place in the WTA Tour Finals without hitting a ball after Dominika Cibulkova was knocked out of the China Open second round on Tuesday.
Radwanska and Pliskova had already all but secured their respective places in Singapore, and Cibulkova's three-set defeat to Cornet in Beijing ensures they cannot drop out of the top eight.
Also in China, Caroline Wozniacki continued her late-season resurgence, Petra Kvitova remains in top form and Simona Halep had little trouble in reaching round three on a day heavily disrupted by rain in China.
CIBULKOVA SUFFERS SINGAPORE BLOW
Cibulkova is currently seventh in the Road to Singapore rankings, but the Slovakian was on the receiving end of a 6-2 5-7 6-2 defeat to Frenchwoman Cornet in a match that lasted almost two-and-a-half hours.
The world number eight was regularly punished on her first serve, winning just 46 per cent of first-serve points against the aggressive Cornet.
Defeat means that Radwanska is guaranteed to return to Singapore to defend her title, while Pliskova will make her debut appearance at the season-ending event to join Angelique Kerber, Serena Williams and Simona Halep - with the trio having already qualified.
KVITOVA JUGGERNAUT ROLLS ON
Kvitova - the 14th seed - maintains an outside chance of reaching Singapore after she saw off local favourite Wang Yafan 6-4 6-1 in little over an hour to set up a meeting with defending champion Garbine Muguruza.
The Czech was champion in Wuhan last week and, after going down a 3-2 break early in the first, won 10 of the remaining 12 games to reach round three.
"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," Kvitova said.
WOZNIACKI, HALEP ROLL ON
Wozniacki had slipped as low as 74th in the world rankings after a poor start to 2016, but a late season resurgence - which includes a title in Tokyo and a semi-final run at the US Open - has seen her close on a top-20 return.
The Dane continued to impress as she made short work of 13th Roberta Vinci in a 6-3 6-2 victory. The 2010 champion now faces Radwanska for the third time in as many weeks in round three.
Halep, seeded fourth, was handed a bye in round one and she appeared fresh in a comfortable 6-2 6-2 beating of Yanina Wickmayer.
Ninth seed Svetlana Kuznetsova, a two-time victor of the China Open, defeated Misaki Doi 6-1 7-5, while Zhang Shuai needed three sets to beat Alison Riske.