KEY BISCAYNE, Fla. (AP) -- Li Na overcame three set points Sunday to rally past American Madison Keys 7-6 (3), 6-3 and reach the fourth round at the Sony Open.
The No. 2-seeded Li, the reigning Australian Open champion, won despite struggling with her second serve. She had seven double-faults and was broken four times.
Keys failed to convert her set points serving at 5-3 in the first set. She also squandered a lead in the second set, when three times she was within a point of going up 3-love.
American CoCo Vandeweghe earned a shot at Serena Williams in the fourth round by winning a match that ended at 2:29 a.m. Vandeweghe, a qualifier ranked No. 104, rallied past 2011 U.S. Open champion Samantha Stosur 5-7, 7-5, 7-5.
The match began shortly before midnight Saturday and ended with a handful of spectators in the stadium.
Vandeweghe has never previously been beyond the first round at Key Biscayne. She'll play the top-ranked Williams on Monday.