Pennetta continues winning at Zurich

ZURICH, Switzerland, Oct. 17 (UPI) -- Unheralded Flavia Pennetta joined Venus Williams and two others in Friday's quarterfinal winners circle at the Zurich Open tennis tournament in Switzerland.

The unseeded Pennetta followed her three-set victory over No. 1 seed Jelena Jankovic Thursday with a 7-5, 6-2 win over Katarina Srebotnik, while Williams, the third seed, banged out a 6-3, 6-3 win over Francesca Schiavone.

In other quarterfinal matches, second-seeded Ana Ivanovic was a 6-1, 6-4 winner over unseeded Petra Kvitova and, in a battle of non-seeds, Anabel Medina Garrigues was tied 4-6, 6-3 with Victoria Azarenka when Azarenka retired with a shoulder injury.

Saturday's semifinal matches have Pennetta against Medina Garrigues and Williams versus Ivanovic.

Williams, a seven-time major champion, is 4-1 lifetime against Ivanovic, who won their only meeting this season in the quarters at the Australian Open.

Sunday's champion will collect a $95,500 first prize check.