Julia Goerges completed the WTA Elite Trophy semi-final line-up with a straight-sets victory over top seed Kristina Mladenovic in Zhuhai.
A seventh straight win for Goerges secured top spot in the Azalea Group with a 6-2 7-6 (7-4) win that booked a final-four clash with Anastasija Sevastova, while CoCo Vandweghe will face Ashleigh Barty for a place in the showpiece.
The German hit 31 winners and made 23 unforced errors as she fought back from 3-5 down in the second set to extend Mladenovic's losing streak to 12 matches.
French Open quarter-finalist Mladenovic had nine double faults and won just 20 per cent of the points on her second serve as she failed to stop the rot prior to 2018.
The day's two other matches ended prematurely, with Elena Vesnina and Sloane Stephens retiring from their final outings at the competitions.
Vesnina shook hands while trailing home favourite Peng Shuai 6-2 1-0, while US Open champion Stephens won just five points before pulling out at 5-0 down to Barbora Strycova.