(CNN) -- Maria Sharapova swept past seventh seed Agnieszka Radwanska in straight sets to reach the quarterfinals of the $2 million WTA tournament in Cincinnati.
The former world number one fought off a determined opponent and stifling heat in Ohio to record a 6-2 6-3 victory in their third round match.
Sharapova, seeded 10th, secured two breaks of service to claim the opening set, but was pushed harder in the second by her Polish opponent, who had two break points in the third game.
Sharapova saved them both and broke through in the sixth game as she took a 4-2 lead with an exquisite lob.
The Russian ace held service comfortably to secure victory on her third match point after just over an hour and a half on court.
Sharapova is making her first appearance at the tournament and faces a tough last eight clash against France's Marion Bartoli, who beat second seed Caroline Wozniacki of Denmark 6-4 6-1 in an earlier upset.
Top seed Jelena Jankovic also departed Thursday as she was beaten 7-6 6-4 by qualifier Akgul Amanmuradova of Uzbekistan.
But fellow Serbian and another former world number one, Ana Ivanovic, continued her fine play with a 6-0 6-3 rout of Elena Vesnina.
Ivanovic will next play Amanmuradova, who reached the semifinals of the event in 2007.
12th-seeded Belgian Yanina Wickmayer also made the quarters by beating the eighth seed Li Na 2-6 6-2 7-6 in a thrilling three-setter.
Italy's Flavia Pennetta beat sixth seed Vera Zvonareva of Russia 6-4 6-3.
She will play the winner of the night match between reigning U.S. Open champion Kim Clijsters and American wild card Christina Mchale from New Jersey.