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.[break]
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.
"I was happy I could stay at the same level from the beginning of the match to the end, it was a pretty good challenge," Li said.
"She has a big serve. It´s very good that I could have the match before the Australian Open to see how strong I am on the court."
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.
"So far I feel good, and I´m very happy that I can play good matches, already seven in a row," she said.
"I think this year it´s the first time I´ve played two tournaments before a Slam. I never did that before.
"So far it´s good, so I´m happy with my performance. I´m going to keep going."
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.
"Today it felt like it was freezing compared to yesterday," she said.
"I think it was perfect weather to play, around 25 degrees (Celsius), but for sure the wind was tough. I think I played quite good in the wind."
While the mercury topped 42 degrees Celsius (107.6 F) in Sydney on Tuesday, it was forecast to peak at just 25 degrees on Wednesday.
Cibulkova was on top of her game, converting five of her six break points and winning 75 percent of her first serves against Errani.
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