Memphis, TN –  Top seed Kirsten Flipkens was a hard-fought second-round winner Wednesday at the $235,000 U.S. National Indoor Tennis Championships.

The Belgian Flipkens snuck past Ukrainian Lesia Tsurenko 7-5, 3-6, 6-3 to secure a quarterfinal berth on the hardcourts at The Racquet Club of Memphis.

Also in the round of 16, Swiss Stefanie Voegele overcame French qualifier Claire Feuerstein 3-6, 7-6 (7-2), 6-1.