Radwanska, who won in Auckland and Sydney, took just one hour and 26 minutes to wrap up a 6-3, 6-3 victory and stay unbeaten this year, reports Xinhua.
Begu surprised the fourth seed by breaking serve in the first game then fighting her way back into the match after Radwanska was serving for the first set at 5-1.
The Romanian also produced a comeback in the second set as Radwanska let go a number of chances.
With top-ranked Azarenka and Williams on the other half of the draw, Radwanska's main obstacles to reach the final are 2011 French Open champion Li Na and potential semifinal rivals Maria Sharapova or No. 5 Angelique Kerber of Germany.
