(Photo credit: Geoff Burke-Imagn Images)

For the third straight day, No. 1 seed Jessica Pegula dropped the opening set but rallied to win, this time defeating seventh-seeded Russian Diana Shnaider 3-6, 6-3, 6-2 to advance into the semifinals of the Charleston Open on Friday.

To make matters even harder, the reigning Charleston Open champion dug herself a 2-0 hole in the third set before rattling off six straight games to clinch the result. Pegula's serve was the difference this time as she had eight aces and no double faults while Shnaider had just one ace to six double faults. In all, Pegula's three matches this week have taken over seven combined hours.

Next up for Pegula is a fellow American, No. 4 seed Iva Jovic, who swept No. 8 Anna Kalinskaya 6-3, 6-4 in 81 minutes to advance into the third tour-level semifinal since September for the 18-year-old.

In the other semifinal, another American in No. 5 seed Madison Keys will face Ukraine's Yuliia Starodubtseva. Keys upended No. 3 Belinda Bencic of Switzerland 4-6, 6-3, 6-2, and the unseeded Starodubtseva denied an all-American set of semifinals by beating McCartney Kessler 6-4, 6-4 to reach her first tour-level semifinal.

Copa Colsanitas Colsubsidio

After a chaotic Thursday where the second and third seeds fell, the two remaining seeded competitors advanced into the semifinals with minimal drama in Bogota, Colombia.

No. 1 Czech seed Marie Bouzkova beat Latvia's Darja Semenistaja 6-1, 7-5. She'll face qualifier Jazmin Ortenzi, who rallied past fellow Argentinian Julia Riera 6-7 (5), 6-3, 6-2 to reach her first WTA semifinal in just her second WTA main draw.

No. 8 Panna Udvardy of Hungary beat Poland's Katarzyna Kawa 7-6 (2), 6-1 and will face home competitor Emiliana Arango, who swept Varvara Lepchenko 6-4, 6-3.

--Field Level Media