Agnieszka Radwanska enters semifinals, Cibulkova stuns Errani

Big guns John Isner and Gilles Simon tumbled out of the ATP/WTA Sydney International on Wednesday as Jarkko Nieminen stayed on course to defend his title.

Towering No. 1 seed Isner lost 6-4, 6-4 to fellow American Ryan Harrison in the second round and raised doubts about whether he will play in next week’s Australian Open with a bruised right knee.

French second seed Simon bowed out of the tournament without hitting a ball, succumbing to a recurring neck injury and giving an opportunity to lucky loser Ivo Klec to face Nieminen.

Finland’s Nieminen polished off the Slovakian world ranked 416th player 6-3, 6-1 in just 46 minutes to set up a quarterfinal showdown with in-form Australian Bernard Tomic.

Nieminen will face a tough test against Tomic, who knocked out German fifth seed Florian Mayer, 7-6(4), 6-2.

Poland’s Agnieszka Radwanska clinched a seventh straight victory to reach the semifinals of the WTA event, as she builds towards next week’s Australian Open.

The world No. 4 and tournament top seed overcame Italian world No. 16 Roberta Vinci, 6-4, 7-5 in just over an hour and a half to move into the last four.

In the bottom half of the women’s draw, Slovakian world No. 15 Dominika Cibulkova upset French Open finalist and tournament third seed Sara Errani of Italy, 6-2, 6-1.

Meanwhile, top seeds David Ferrer and Philipp Kohlschreiber both survived scares to reach the quarterfinals of the ATP Heineken Open in Auckland.

Defending champion and No. 1 seed Ferrer suffered a mid-match slump as he came under pressure from Lu Yen-Hsun of Taiwan in the warm-up event for next week's Australian Open, eventually grinding out a 6-4, 2-6, 6-3 victory.

Kohlschreiber, the second seed, was also unconvincing and committed 52 unforced errors and four double faults in a rusty 7-6(4), 4-6, 6-3 win over Colombian Alejandro Falla.

A wild card entry in Auckland, Monfils lines up against Tommy Haas in the last eight after the German third seed downed Igor Sijsling 6-3, 6-4.

Fourth seed Sam Querrey defeated Belgium’s Olivier Rochus 7-5, 6-3 to set up a quarterfinal with Jesse Levine of Canada.

Hewitt tames Raonic

Australian veteran Lleyton Hewitt tamed big-serving Milos Raonic on Wednesday, surviving 20 aces from the Canadian to post an opening 6-3, 1-6, 7-6(4) win at the Kooyong Classic in Melbourne.

Argentine Juan Martin del Potro beat Frenchman Paul-Henri Mathieu, a late substitute for injured Argentine Juan Monaco, 6-4, 3-6, 7-6(3).

Tomas Berdych beat Ivan Dodig of Croatia, who replaced injured Kei Nishikori of Japan, 4-6, 6-2, 6-3.

The results:

At Sydney: ATP/WTA International: Men: Second round: Julien Benneteau bt Radek Stepanek 0-0 (retd.); Denis Istomin bt Fernando Verdasco 6-3, 6-3; Marcel Granollers bt Fabio Fognini 6-2, 7-6(4); Kevin Anderson bt Feliciano Lopez 6-3, 6-4; Jarkko Nieminen bt Ivo Klec 6-3, 6-1; Ryan Harrison bt John Isner 6-4, 6-4; Bernard Tomic bt Florian Mayer 7-6(4), 6-2; Andreas Seppi bt John Millman 6-2, 3-6, 6-3.

Women: Quarterfinals: Agnieszka Radwanska bt Roberta Vinci 6-4, 7-5; Dominika Cibulkova bt Sara Errani 6-2, 6-1; Li Na bt Madison Keys 4-6, 7-6(2), 6-2; Angelique Kerber bt Svetlana Kuznetsova 6-3, 7-5.

At Auckland: ATP Heineken Open: Second round: David Ferrer bt Lu Yen-Hsun 6-4, 2-6, 6-3; Philipp Kohlschreiber bt Alejandro Falla 7-6(4), 4-6, 6-3; Sam Querrey bt Olivier Rochus 7-5, 6-3; Xavier Malisse bt Santiago Giraldo 7-6(6), 6-4; Lukas Lacko bt Thomaz Bellucci 6-3 7-5; Jesse Levine bt Brian Baker 7-5, 6-4; Gael Monfils bt Greg Jones 6-4, 6-2.

At Melbourne: ATP Kooyong Classic: First round: Juan Martin del Potro bt Paul-Henri Mathieu 6-4, 3-6, 7-6(3); Lleyton Hewitt bt Milos Raonic 6-3, 1-6, 7-6(4); Marcos Baghdatis bt Janko Tipsarevic 6-1, 1-0 (retd.); Tomas Berdych bt Ivan Dodig 4-6, 6-2, 6-3.

At Hobart: WTA International: Second round: Jarmila Gajdosova bt Olga Govortsova 6-3, 6-1; Kirsten Flipkens bt Bojana Jovanovski 6-3, 6-2; Tsvetana Pironkova bt Klara Zakopalova 3-6, 6-4, 6-2; Monica Niculescu bt Peng Shuai 3-6, 6-4, 6-4.

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