Istanbul - Urszula Radwanska of Poland beat the last surviving seed in the Istanbul Cup quarterfinals when she outlasted No. 8 Tsvetana Pironkova of Bulgaria 6-2, 3-6, 7-6 (5) on Friday.
Radwanska next faces Roberta Vinci of Italy, who stumbled after dominating the first set against Magdalena Rybarikova. The Slovak rallied to beat Vinci 0-6, 7-5, 6-2.
In reaching the semis, Radwanska earned her best result on tour in three years. She was bothered by right shoulder and right leg injuries over the last two years. The younger sister of top-10 player Agnieszka Radwanska, Urszula was still searching for her first WTA singles title. She won the doubles here eight years ago with Agnieszka.
She took more than two hours to beat Pironkova in a match with 17 service breaks.
Lesia Tsurenko endured a similar struggle to overcome fellow Ukrainian Kateryna Bondarenko 7-6 (13), 7-5 for the first time in three meetings. There were 13 service breaks in the 2 1/2-hour match.
In the semifinals Tsurenko plays Kirsten Flipkens, who defeated Francesca Schiavone of Italy 6-2, 6-4. The Belgian proved far more decisive in winning her break points — 67 to 20 percent for Schiavone.
This is only the second tournament this year in which Tsurenko has excelled. She came out of qualifying to reach the quarterfinals at Indian Wells in March, beating two top-10 players.