China's Peng Shuai, seeded 13, edged off 19th seed Julia Goerges of Germany 6-4, 7-6 (1), advancing into the last 16 of U.S. Open on Friday.

Peng, who reached the fourth round in both the Australia Open and Wimbledon, extended her hot form and accomplished personal best at the Flushing Meadow, eliminating her first three opponents all in straight sets.

Peng was broken at the opening game, but returned two breaks as the match moved on to win the first set in 6-4.

It was again Peng that was broken in the first game of second set, allowing a double fault, but the Chinese just step up the attack and pulled out a break in the subsequent game, forcing a 1-1.

Peng missed one match point in the 10th game and failed to take another three match point in the 12th game, but the German managed to hold on and prolonged the match into tiebreak.

Peng put on a dominant play in the tiebreak and soon built up a 6-1 lead and wrapped it up with an ace.

Goerges committed a total of 44 unforced errors against Peng's 19.

"At the first a couple of games, I was trying to find my rhythm and adjusting myself to the surface of the court," said Peng in explaining her broken game in the opener.

"I had never played her before the match, so I need to learn her way of playing at first. After two to four games, I feel I'm okay with the wind and the surrounding. So I think I was going into the right track.

"She (Goerges) is aggressive and hard in her forehand, but it turned out more errors. For her backhand, it's less powerful but with no many errors. She served really good," added Peng.

The last 16 is the best ever performance for Peng, who enjoyed career best season so far.

"Last year, I was bothered by arm muscle injury and I failed to make the fourth round. This year, I was not free from injury either," said Peng.

"My left hip is not good. For this, I had to pulled out of the Rogers Cup and Cincinnati Masters half way and also skipped the Texas Open. I just want to give some time and injury for my recovery in the U.S. Open.

"Now everything is fine. Though the injury is not 100 percent cured, but it's good enough to support my playing here. Everyting pays off so far?

Peng will next play Flavia Pennetta, the No. 26 seed, who stunned Russia's third seed Maria Sharapova 6-3, 3-6, 6-4.

"It's gonna be really tough. She's in good shape. She play really good in the last summer. It's gonna be tough against her. She really aggressive in her game. She serves really good," Pennetta said of Peng.

"I have to be really aggressive and try to move her a lot."