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.
Radwanska, coming off a victory in Auckland last week where she beat Yanina Wickmayer in the final, will now face 2011 winner Li Na (left) 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 No 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.