This was their fifth encounter and the 27-year-old Pole won for the fifth time. This also marks the fifth time for Radwanska to make it to the last 16 of the French Open.
She next faces Bulgaria's Tsvetana Pironkova, who dispatched Sloane Stephens of the United States 6-2, 6-1.
World number two Radwanska started her Roland Garros campaign with straight-set wins over Serbia's Bojana Jovanovski and France's Caroline Garcia. (PAP)
gs/