Zhang Shuai is the lowest-ranked participant at the WTA Elite Trophy in Zhuhai, but became the first player to reach the semi-finals of the event on Thursday.
Wildcard entry Zhang followed up her opening-day thrashing of Timea Bacsinszky with a 7-6 (7-2) 6-4 triumph over Timea Babos, a late inclusion in the field following Carla Suarez Navarro's withdrawal through injury.
Needing to win just four games to qualify from the Camellia Group, Zhang fell 4-1 down in the opening set but fought back impressively to claim a popular victory on home soil.
"I didn't want to think too much about winning four or five games, because I wanted to win the match," said the Chinese.
"I'd played really good during the Asian Swing so I have a lot of confidence now, and I want to win every match."
Elina Svitolina is also through to the last four, the Ukrainian holding two wins from two in the Rose Group after a 6-4 6-2 victory over Elena Vesnina.
Caroline Garcia faces a winner-takes-all match against top seed Johanna Konta in the Azalea Group, after eliminating Samantha Stosur with a 6-4 6-3 success over the Australian.
The other semi-final place will go to either Petra Kvitova or Barbora Strycova, whose meeting precedes the match between Garcia and Konta on Friday.