Jessica Pegula bounced back from a first-set stumble to secure a 6-7(2), 6-2, 6-1 win over American compatriot Emma Navarro on Friday and reach the China Open semi-finals where she will face Czech Linda Noskova.
Noskova, seeded 26th, thumped unseeded Briton Sonay Kartal 6-3, 6-4 earlier on Friday to ensure her first appearance in the final four of a WTA 1000 tournament.
World number seven Pegula got a break early in the first set, but Navarro saved three set points to make it 5-5 before prevailing in the tiebreak.
However Pegula, a former US Open finalist, kept her cool and dominated the next two sets, securing her third win in a row against Navarro.
"She did a good job of staying tough, but at the same time I felt I was playing the right way," Pegula said.
"I told myself to not get too frustrated. That kind of allowed me to play more free."
Noskova outplays Kartal
Noskova's win over Kartal made her the third player born since 2004 to reach 10 semi-finals on the WTA circuit, alongside Coco Gauff and Diana Shnaider.
The 20-year-old is set to make her top 20 debut when the updated WTA rankings are released on Monday.
Noskova started brightly, breaking Kartal early to take a 3-1 lead in the opening set. The Briton, who stunned Russian fourth seed Mirra Andreeva in the previous round, rallied to level at 3-3, but Noskova reclaimed control, converting her third break point and closing out the set.
The second set proved tighter, with Kartal breaking Noskova's serve to lead 2-0. But the Czech responded decisively, sealing the win in one hour and 10 minutes.
Noskova will play Pegula on Saturday after American compatriots Gauff and Amanda Anisimova meet in the first semi-final.