Sports

Del Potro beats Stepanek, advances to Sydney International semifinals against Tursunov

  • Juan Martin del Potro of Argentina plays a forehand shot in his quarterfinals match against Radek Stepanek of the Czech Republic during the Sydney International Tennis Tournament in Sydney, Australia, Thursday, Jan. 9, 2014. (AP Photo/Rob Griffith)

    Juan Martin del Potro of Argentina plays a forehand shot in his quarterfinals match against Radek Stepanek of the Czech Republic during the Sydney International Tennis Tournament in Sydney, Australia, Thursday, Jan. 9, 2014. (AP Photo/Rob Griffith)  (The Associated Press)

  • Radek Stepanek of the Czech Republic throws his head back as he cries out after missing a shot in his quarterfinals match against Juan Martin del Potro of Argentina during the Sydney International tennis tournament in Sydney, Australia, Thursday, Jan. 9, 2014. (AP Photo/Rob Griffith)

    Radek Stepanek of the Czech Republic throws his head back as he cries out after missing a shot in his quarterfinals match against Juan Martin del Potro of Argentina during the Sydney International tennis tournament in Sydney, Australia, Thursday, Jan. 9, 2014. (AP Photo/Rob Griffith)  (The Associated Press)

Top-seeded Juan Martin del Potro beat Czech veteran Radek Stepanek 6-4, 3-6, 6-3 on Thursday to set up a Sydney International semifinal against Russia's Dmitry Tursunov.

Del Potro, the 2009 U.S. Open champion who finished last season ranked No. 5, relied on his strong serve, with 14 aces to three, and saved seven of ten break points.

Tursunov had a 7-6 (5), 6-2 win over Denis Istomin of Uzbekistan. Defending champion Bernard Tomic was playing Alexandr Dolgopolov of Ukraine in a later quarterfinal.

At Hobart, top-seeded Sam Stosur reached the semifinals with a 6-3, 6-2 win over No. 34-ranked Bojana Jovanovski of Serbia.

The 2011 U.S. Open champion next faces seventh-seeded Klara Zakopalova of the Czech Republic, who beat American Alison Riske 6-4, 7-5.