NEW YORK, Aug. 31 -- World No. 39 Peng Shuai defeated Lucie Safarova of the Czech Republic 6-3, 6-4 to reach US Open quarter-finals, marking her first final eight appearance in Grand Slam tournaments in her career.

Peng has previously reached Grand Slam fourth round five times, but she lost all of them. Playing her 37th Grand Slam tournament, Peng finally found a way out.

"It's a good match," said Peng, who had lost four of five previous encounters with Safarova.

"I had played her many times and she won much more than me, but there were also some close matches."

Peng was one of the best doubles players on the globe, holding two Grand Slam doubles titles and once the world No. 1 ranking, but she had been waiting for her singles breakthrough for years, until Sunday.

Peng converted both of her break opportunities -- one in each set -- and hit as many as nine aces. She made just seven unforced errors throughout the match, 14 fewer than her 14th-seeded opponent.

"I don't know how many aces I had, but I know I had one on the match point," said Peng.

The victory made Peng the third Chinese player to reach a Grand Slam quarterfinal, after Li Na and Zheng Jie.

"It's amazing, so happy, so excited," said Peng about her accomplishment. "I jumped when I won the match, and I normally wouldn't do that. All the time in Grand Slams I think maybe I can take one more step, one more step."

Having taken down the fourth-seeded Agnieszka Radwanska and 28th-seeded Roberta Vinci en route to the final eight, Peng will be meeting 17-year-old Swiss Belinda Bencic, who eliminated No. 9 seed Belinda Bencic in the same day.

Peng, now in the second week of a major for the first time, will have to learn to manage competition and herself as well. "I just need more rest, more focus," said Peng.