Last year at the Madrid Open, Li Na lost in her first match to American Madison Keys.
Last year at the Madrid Open, Li Na lost in her first match to American Madison Keys.
Julian Finney/Getty Images

MADRID (AP) - Seeded women's players Li Na and Agnieszka Radwanska overcame stubborn resistance to win their first-round matches at the Madrid Open on Monday.

The second-seeded Na held off Belgium's Kirsten Flipkens 6-1, 7-6 (7) before the third-seeded Radwanska ousted Canada's Eugenie Bouchard 7-6 (3), 6-2 on the clay at the Magic Box.

Na will next face fellow Chinese player Jie Zheng.

In men's first-round play, ninth-seeded John Isner beat qualifier Teymuraz Gabashvili 7-6 (8), 6-4, with the American securing the only break in a match heavy on baseline groundstrokes.

Also, 10th-seeded Kei Nishikori followed up his Barcelona Open triumph with a 6-4, 6-4 win against Ivan Dodig of Croatia.

Jo-Wilfried Tsonga beat fellow Frenchman Edouard Roger-Vasselin 6-3, 4-6, 6-3.

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