Zheng Qinwen crushed Jasmine Paolini to secure a place in the WTA Finals last four on her tournament debut.
The 22-year-old, China’s Olympic gold medallist in the summer, showcased her power in an easy 6-1 6-1 win that eliminated Italian Paolini.
It left Zheng with a 2-1 group-stage record, with her sole loss coming against Aryna Sabalenka on the first day of the tournament.
She is the second Chinese woman to reach the semi-finals of the tournament following the legendary Li Na in 2013.
“I didn’t know what would happen when I came here,” said Zheng. “I just told myself to enjoy it, especially because I am in a really difficult group.”
Having already clinched the year-end world number one ranking, Sabalenka will top the group if she beats Elena Rybakina later on Wednesday.
The tournament, contested between the top eight singles and doubles players, offers record prize money, with an unbeaten singles champion set to collect just under £4m.
The WTA Finals are being held in Saudi Arabia for the first time – a move which has been criticised by some because of the country’s human rights record.