Prague, Czech Republic (SportsNetwork.com) - Top-seeded Karolina Pliskova was a three-set quarterfinal winner Thursday at the Prague Open.

The world No. 14 Czech star was tested by wild card fellow countrywoman Denisa Allertova, but prevailed for a 6-2, 5-7, 6-1 decision at this clay-court event.

Pliskova's semifinal opponent on Friday will be capable Belgian Yanina Wickmayer, who came from behind to beat qualifier Danka Kovinic of Montenegro 2-6, 6-3, 6-3 on Day 4.

The other semi will pit qualifier and 2011 Prague champion Lucie Hradecka against 18-year-old fellow Czech Katerina Siniakova, who upset third- seeded compatriot Barbora Strycova 6-4, 6-2. Strycova was a runner-up here back in 2010.

Hradecka advanced by besting wild card fellow Czech Klara Koukalova 7-5, 4-6, 7-5.

Three of the four semifinalists hail from the host nation Czech Republic.

The 2015 Prague titlist will collect $43,000.