Petkovic advances, Errani upset in Charleston

Carla Suarez Navarro hits a forehand against Andrea Petkovic (not pictured) in a women's singles semi-final on day eleven of the Miami Open at Crandon Park Tennis Center. Navarro won 6-3, 6-3. Mandatory Credit: Geoff Burke-USA TODAY Sports

(Reuters) - Andrea Petkovic battled back to advance to the semi-finals at the Family Circle Cup in Charleston, South Carolina on Friday while Czech qualifier Lucie Hradecka upset yet another seed with a victory over Sara Errani.

Last year's champion Petkovic had to rally from a set down to overcome qualifier Danka Kovinic 2-6 6-3 6-1 to set up a semi-final against fifth-seeded fellow German Angelique Kerber, who beat Romania's Irina-Camelia Begu 7-6 7-6.