The fourth seed, who won tournaments in Auckland and Sydney ahead of the Australian Open, will play 2011 French Open champion Li Na of China in the quarter-finals, reports Xinhua.
In the bottom half of the draw, Radwanska, Li and second seed Maria Sharapova are yet to drop a set. But Radwanska had never made it past the quarter-finals in Melbourne.
Radwanska hit just 14 winners to Ivanovic's 35, but made a remarkably low four unforced errors compared to the Serb's 34.
After Radwanska cruised through the first set in just 27 minutes, Ivanovic, a former World No.1 and Australian Open finalist, tried to increase the tempo in the second, charging to the net more often.
It worked to an extent, making the match much more of a contest.
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But Radwanska still eventually wore down the crowd favourite, in what was the Polish girl's fifth straight victory over Ivanovic.