China's fifth-seeded Li Na smacked 19 winners and fought off a late comeback bid to defeat American Varvara Lepchenko 6-2, 6-4 Saturday to reach the fourth round of the WTA and ATP Miami Masters event.
Li had been sidelined for seven weeks after hurting her left ankle in the Australian Open final, which she lost to Victoria Azarenka.
With Saturday's win, she improved to 16-2 on the season and booked a date in the round of 16 against the winner of a later match between Danish ninth seed Caroline Wozniacki and Spain's Garbine Muguruza.
Lepchenko made 19 unforced errors in falling to 4-7 for the season.
Li dominated the opening set, dropping only five points on her serve while Lepchenko managed only one winner against 10 unforced errors.
Li jumped ahead 4-2 in the second set before Lepchenko managed her first break-point chance. The American took advantage with a net cord winner to break back and then held to level the set at 4-4.
After holding, Li ended matters in the 10th game. Lepchenko hit a backhand winner and Li netted a backhand attempt on the Chinese star's first two match points but Li smashed a forehand winner on her third match point for the victory.