China's Peng Shuai reached the first Grand Slam singles quarterfinal of her career on Sunday, toppling 14th-seeded Lucie Safarova 6-3, 6-4 to reach the US Open last eight.

Peng, who had five Grand Slam fourth-round appearances on her resume but had never cracked the quarterfinals, fired nine aces past her Czech opponent - including one on match point to seal the win after one hour and 11 minutes.

"I don't know how many aces I had but I know I had one on the match point," said Peng, who had lost four of five previous encounters with Safarova.