NEW YORK - American 12th seed Coco Gauff battled hard to edge out Chinese veteran Zhang Shuai 7-5, 7-5 on Sunday, reaching the US Open women's singles quarterfinals.

Two-time Grand Slam quarterfinalist Zhang broke first in the second game, but the 18-year-old Gauff returned two breaks soon to take a 4-3 lead in the first set.

Although the 33-year-old Zhang filled the gap in the eighth game, the world No. 12 took two games in a row after 5-5 to win the opening set 7-5.

The duo seesawed in the second set with Zhang broke first again. But this year's French Open finalist Gauff performed phenomenally with speed and strength, winning in 7-5 to reach the quarterfinals after one hour and 56 minutes.

Gauff will fight for a semifinal berth against French player Caroline Garcia.