The Bronx Open saw another big upset as American wild card Bernarda Pera eliminated third seed Barbora Strycova 3-6, 6-2, 6-1.
The Czech had dominated their only previous meeting, but Pera was able to turn the tables to advance to a quarterfinal matchup with fifth seed Katerina Siniakova.
Pera stages comeback to reach quarterfinals
Strycova was applying pressure immediately, attaining four break points in the American's opening two service games, but she was unable to convert.
The Czech was having little trouble holding and in the seventh game, she finally made the breakthrough after a pair of unforced errors from Pera.
Two aces in her next service game was the foundation for a hold as Strycova stretched her lead to 5-3 and she closed out the set on her third chance after forcing Pera to net a return.
The American turned the tables in the second set, breaking with a winner at net for a 2-1 lead. A hold made it 3-1, but her next hold wouldn't be as easy, staving off a break point for a 4-2 advantage.
Strycova double-faulted twice in the seventh game to hand Pera a second break and the American closed out the set a game later to level the match.
Pera was the aggressor in the final set, blasting returns to set up double break point to which Strycova double faulted. A second break was achieved with an overhead winner.
The third seed got one break back to trim the deficit to 3-1, but Pera ran off the final three games of the match to reach the last eight.
"I wasn't focused on her game. I was more focused on my game and finding the right balance", Pera said of turning around the match. "It's about finding the right balance between being passive and aggressive.
"It's about finding the right balance and rhythm with my feet in the second set and keep going the same way in the third."