Strasbourg, France (SportsNetwork.com) - Former champion Andrea Petkovic was a quarterfinal upset victim Thursday at the Strasbourg International tennis event, a final French Open tune-up.
Promising Puerto Rican Monica Puig upended the fourth-seeded German Petkovic 6-4, 6-4 on the red clay at Strasbourg Tennis Club.
The former top-10 star Petkovic titled here three years ago.
A pair of American reached the semifinals, as Christina McHale was leading Zarina Diyas 6-2, 3-1 when the Kazakhstani retired on Day 4, while Madison Keys took out German Julia Goerges 6-2, 2-6, 6-2.
One other quarterfinal saw Spaniard Silvia Soler-Espinosa defeat Italian Camila Giorgi 3-6, 6-4, 7-5.
Friday's all-non-seed semis will pit Keys against Puig and McHale versus the qualifier Soler-Espinosa.