New York, Sep 8 (IANS): Romanian second seeded Simona Halep earned a hard-fought victory against German tennis player Sabine Lisicki, 6-7(8), 7-5, 6-2 to book her first women's singles quarterfinal berth at the US Open here.

Halep, playing her sixth US Open, will now take on Belarusian Victoria Azarenka, ranked 20th, who defeated American Varvara Lepchenko 6-3, 6-4. Both Halep and Lisicki broke each other several times in the first set on Monday until it progressed to a tie-break which the German won through her superior stroke play, reports Efe.

The second set seemed to be going the same way, before Halep managed to clinch it by pulling off one break more than her opponent, taking the match to the third set.

With the match poised at one set all, Lisicki lost steam and was unable to match her opponent's consistency in the deciding set, ultimately bowing out of the Open.

Halep committed 72 unforced errors and hit 37 winners to Lisicki's 33 and 18 respectively, in the match lasting two hours and 38 minutes.

The Romanian also converted 10 of 11 breakpoint opportunities, compared to seven of 13 by her rival, while both committed six double faults each.

Meanwhile, Italy's 26th-seeded Flavia Pennetta reached the quarterfinals yet again after defeating Australia's 22nd-ranked Samantha Stosur 6-4, 6-4.

Pennetta played a perfect game to reach her fourth consecutive US Open quarterfinal and sixth in 11 appearances in the tournament, in a mere one hour, 18 minutes. The 33-year-old Italian's ability to find the perfect moment in each set to break her opponent's serve proved decisive in the win.

Pennetta, who held her serve throughout the match, broke Stosur twice, while smashing seven aces and committing two double faults to her opponent's seven and three respectively.

Pennetta also struck 18 winners and committed 13 unforced errors to Stosur's 21 and 35 respectively.

The Italian will face fifth seeded Czech Petra Kvitova, who notched a 7-5, 6-3 win over British sensation Johanna Konta, who had proved to be the nemesis of ninth seed Spaniard Garbine Muguruza in the second round.

Konta, who has had a dream run in the US Open, was no match for Kvitova's consistency and performance during the one hour and 28 minutes the match lasted.

Kvitova, who is set to play her first quarterfinal of the tournament, hit 28 winners and committed 22 unforced errors to her opponent's 10 and 21 respectively.