New York - Chinese fifth seed Li Na advanced to the fourth round of the US Open on Friday, smacking 11 aces in a 6-2, 7-5 victory over British teen Laura Robson.
Li avenged a third-round loss to Robson in last year's tournament and will next face either Japanese qualifier Kurumi Nara or Serbian ninth seed Jelena Jankovic for a berth in the quarter-finals.
"I was really happy how I was hitting on the court," Li said. "And I thought I served really well."
Connecting on 65 percent of her first serves and winning all nine points when she came to the net, the 2011 French Open winner took control early and kept it most of the match.
Li said that even her coach, former Justine Henin mentor Carlos Rodriguez, would have to say he liked her effort, even though she said he would have a different message for her during practice.
"He would think I can come even more to the net," she said.
Li broke Robson to open the match and again in the fifth game on her way to capturing the first set after 29 minutes, aided by 15 Robson unforced errors.
Robson broke for a 2-0 lead in the second set when Li sent a forehand wide but Li broke back in the fifth and again in the penultimate game for a victory that came after 81 minutes when Li swatted a second-serve ace.
Robson, 19, failed to match her best Slam showings, which came last year when she made the last 16 by beating Li and in July at Wimbledon.
In New York, she was the first British woman to be seeded at a Grand Slam since Jo Durie at the 1987 Australian Open.
Li, 31, seeks her eighth career crown and second of the year after a home-soil title at Shenzhen.
"I'm still young," Li said. "I can do even more hard work."