Qinwen Zheng booked her place in the last four of the WTA Finals with a dominant 6-1 6-1 victory over Jasmine Paolini. (More Tennis News)
The Olympic gold medallist hit 12 aces as she powered past this season's French Open and Wimbledon finalist in just over an hour in Riyadh.
This was the winner-takes-all clash in Purple Group, with both players aiming to join world number one Aryna Sabalenka in the semi-finals.
The form player since Wimbledon with 29 wins from 34 matches - also including titles in Palermo and Tokyo, plus a run to the final in Wuhan - Zheng quickly asserted her authority on proceedings.
The 22-year-old scored five breaks of serve on the way to becoming the youngest semi-finalist on her WTA Finals debut since Petra Kvitova in 2011.
"Finally, I showed off some tennis I really want to play," she said. "Of course, when you enter the match, you are nervous, but at the same time, you feel confidence because you know your level. And I know how capable I am.
"I remember in 2022, my serve was quite strong. I don't know why but, suddenly in 2023, my serve started to drop. In this tournament and the rest of this half-year, it is the first time I've felt like the serve is starting to come back."
Beating two top-10 players in the same tournament for the first time, Zheng is the first Chinese player to achieve the feat since Li Na (four) at this event 11 years ago.
The seventh seed also follows in the footsteps of Na and Kimiko Date in 1994 as one of three players representing an Asian country to reach the last four at the WTA Finals.
Sabalenka's place in the semi-finals was already secured, rendering her 6-4 3-6 6-1 defeat by Elena Rybakina academic, though ending a seven-match winning streak.
Having shared the two meetings this season in Brisbane and Madrid, the players took a close set each here, but it was one-way traffic in the decider.
In the final match of her first tournament since withdrawing from the US Open with a back injury, Rybakina did not face a single break point in the final set, while winning all 12 points on her first serve, to bow out with victory.
Though academic, it was an historic victory for the Kazahstani, who became the first player representing an Asian country to defeat the world number one at the WTA Finals.
Rybakina is also the fourth player to achieve six or more wins over the WTA's number one across a two-season span, after Tracy Austin (1979-80), Venus Williams (1999-00) and Lindsay Davenport (2000-01).
