Teenager Aryna Sabalenka and second seed Timea Babos sealed their places in the semi-finals on a rain-affected day at the Tashkent Open.
Sabalenka will play in the last four of a WTA singles event for the first time after the 19-year-old from Belarus beat Kateryna Kozlova 7-6 (7-5) 3-6 6-1 on Thursday.
The unheralded world number 119 only played in the main draw of a WTA event for the first time this year and stands on the brink of a maiden final in Uzbekistan.
Sabalenka belted down nine aces and broke the Kozlova serve five times to set up an encounter with Babos.
Babos, a beaten finalist in her last tournament in Quebec, was a 6-3 6-4 winner against Stefanie Voegele.
The Hungarian did the damage at the start of both sets, opening up a 4-0 lead in the first and winning the first three in the second.
Vera Zvonareva was leading Aleksandra Krunic 3-2 when they were forced off due to the weather and they will complete their quarter-final on Friday, while Kateryna Bondarenko and Kurumi Nara are yet to start their match.