Zhuhai - Australia's Ashleigh Barty stunned former world number one Angelique Kerber in straight sets to reach the WTA Elite Trophy semi-finals on Thursday.
Twenty-one-year-old Barty, the youngest player at the season-ending tournament in China, needed just one hour and 11 minutes to down her German opponent 6-3, 6-4 at Zhuhai's Hengqin International Tennis Center.
It follows an impressive victory over fourth seed Anastasia Pavlyuchenkova of Russia on Wednesday, also in straight sets.
"I felt like I served great today," Barty told media after Thursday's match.
"I... put myself in a good position in my service games to then be super-aggressive and nice and clear when returning so I can, you know, have a little bit more of a crack and then see if I can get some of those early breaks in the sets."
Barty got off to an impressive start against eighth seed Kerber, securing a break in the sixth game and then firing an ace to win the set.
The pair exchanged breaks at the beginning of the second set as Kerber fought back, but Barty prevailed, helped by her 11 aces to the German's two.
The pair's sole previous meeting was in Brisbane in January when Kerber, then world number one and the reigning Australian and US Open champion, survived a big scare from the Australian wildcard entry.
"It was a bit of a... full circle for us, with the start and the end of the season. But, no, I felt like I was in a very different situation this time around," Barty said.
The 2011 junior Wimbledon champion has enjoyed a resurgence since returning to tennis in 2016 after a spell with the Brisbane Heat cricket team.
She began the year ranked outside the top 300 but has since soared to world number 20 and recently became Australia's number one.
She reached her first Premier 5 tournament final in Wuhan in September after crushing French Open winner Jelena Ostapenko of Latvia, but ultimately fell to Caroline Garcia.
Later Thursday, Latvian fifth seed Anastasija Sevastova overpowered Czechoslovakia's Barbora Strycova 6-3, 6-4.
Sevastova, on a career-high ranking of world number 15, also hammered US Open champion Sloane Stephens on Wednesday -- leaving the American with her third successive defeat since winning the US Open.
But Coco Vandeweghe, the number two seed, also from the US, managed to triumph over Russia's Elena Vesnina in the final singles match of the day Thursday with a score of 6-3, 6-2.
The results mean Vandeweghe and Sevastova have also booked their spots in the semis of the round robin tournament.
Result from the third day of the WTA Elite Trophy tournament in Zhuhai, China, on Thursday (x denotes seeding):
Ashleigh Barty (AUS x9) bt Angelique Kerber (GER x8) 6-3, 6-4
Anastasija Sevastova (LAT x5) bt Barbora Strycova (CZE x11) 6-3, 6-4