Li Na of China returns a forehand to Kirsten Flipkens of Belgium during their match at the Madrid Open tennis tournament May 5, 2014. [Photo/Agencies]

MADRID - Second-ranked Li Na started her Madrid Open campaign by overcoming a stubborn opponent just as third-seeded Agnieszka Radwanska did to reach the second round on Monday.

Li's clay debut began with an encouraging 6-1, 7-6 (7) victory over Belgium's Kirsten Flipkens before Radwanska also advanced thanks to a 7-6 (3), 6-2 win over Canada's Eugenie Bouchard.

Li, the Australian Open champion, survived two set points by Flipkens, and eventually took the tiebreaker to avoid another surprise first-round exit like last year. Li goes up against fellow Chinese player Zheng Jie next.

Bouchard came out on the losing end of a tough match against third-ranked Radwanska, as the Polish player earned her 25th match win of the season.

"The tiebreak was the biggest key," said Radwanska, who goes on to play Svetlana Kuznetsova. "I did a couple of good shots in the tiebreak and managed to win that, and that gave me more confidence in the second set."

Kuznetsova held off Alize Cornet of France 6-3, 4-6, 6-1 as the Russian continued her good run, including reaching the final in Portugal on Saturday.

Also, Caroline Wozniacki was a 6-2, 6-2 victor over Ekaterina Makarova while Spanish player Carla Suarez Navarro followed up from winning her first career title in Portugal with a 7-6 (6), 6-4 win over Yvonne Meusburger of Austria. Ninth-seeded Dominika Cibulkova of Slovakia was bounced 6-4, 6-0 by Samantha Stosur of Australia.

A minute's silence was scheduled to be held at the Magic Box's Manolo Santana center court before the evening match in remembrance of Elena Baltacha, a former top-50 British women's player who died of liver cancer on Sunday.