New York, Aug 31 (IANS): China's women's singles tennis player Li Na had paid special attention to her third round match against British teenager Laura Robson, who surprisingly knocked her out of the US Open in the same round last year.

Li didn't let that happen again. The fifth seed powered 11 aces, beating her 12-year younger opponent 6-2, 7-5 to reach the last 16 Friday, reports Xinhua.

"I think since last year I have improved a lot, especially when it comes to the serve and at the net," said Li.

The first set began with a break from Li. The former French Open champion made full use of Robson's mistakes, breaking twice to establish a 4-1 lead. Both players were able to hold their serves in the rest of the games of the first set, which finished with Li's 6-2 win.

Robson stroked much better in the second set. The Briton made a break in the second game and found herself leading 3-0. However, three games were not enough to defeat the World No.6. Li shrugged off the pressure to keep her second service game and break back in the next to get back into match.

The two players went into the 11th game with scores 5-5. Li awarded herself three straight break points by leading 40-0. Robson saved the first two break points but failed in the third. The match went in favour of Li in the 12th game and the 31-year-old veteran sealed the victory after wasting one match point.

"I'm disappointed about today, for sure, and I thought I could have played a lot better. All in all, I guess it was an average week," said Robson.