SYDNEY, Australia (AFP) — Poland’s Agnieszka Radwanska clinched a seventh straight victory to reach the semi-finals of the Sydney International yesterday, as she builds towards next week’s Australian Open.

The world number four and tournament top seed overcame Italian world number 16 Roberta Vinci, 6-4, 7-5 in just over an hour and a half to move into the last four.

Radwanska, coming off a victory in Auckland last week where she beat Yanina Wickmayer in the final, will now face 2011 winner Li Na of China.

Li took two hours and 19 minutes to down teenage American qualifier Madison Keys, 4-6, 7-6 (7/2), 6-2 in a night match.

In the bottom half of the women’s draw, Slovakian world number 15 Dominika Cibulkova upset French Open finalist and tournament third seed Sara Errani of Italy, 6-2, 6-1.

Cibulkova, who eliminated 2011 Wimbledon champion Petra Kvitova in the opening round, will face German second seed Angelique Kerber in the other semi.

Kerber overcame former US and French Open champion Svetlana Kuznetsova 6-3, 7-5 in the last night match.

While the men’s tournament has been strewn with injury withdrawals ahead of next week’s year-opening Grand Slam, Radwanska said she was relishing her run of matches leading into the Australian Open.

Runner-up to Serena Williams at Wimbledon last year, Radwanska found it tough going in the wind against Vinci, whose backhand slice troubled the top seed.

While the mercury topped 42 degrees Celsius in Sydney on Tuesday, it was forecast to peak at just 25 degrees yesterday.

Cibulkova was on top of her game, converting five of her six break points and winning 75 per cent of her first serves against Errani.