Fourth-seeded Coco Gauff reached the quarterfinals for the first time since she won the title in 2023, beating 18-year-old US compatriot Iva Jovic 6-1, 6-4.
Gauff next faces fifth-seeded French Open champion Mirra Andreeva, a 5-7, 6-4, 6-3 winner over Anastasia Potapova.
Zverev once again closed the action on Ashe, beating 21st-seeded Italian Luciano Darderi 6-2, 6-2, 7-6 (7/3).
The French Open champion has become a late-night fixture, playing into the small hours in his first three matches, including two five-setters.
He was in control against Darderi, saving the lone break point he faced and cruising through the first two sets before Darderi stepped things up to force the third-set tiebreaker.
Zverev wrapped it up quickly there, giving himself a match point with a forehand winner to the corner and finished up before midnight with an ace.
Zverev will play Botic van de Zandschulp for a place in the semifinals.
The Dutch player saved a match point as he rallied from two sets down to beat France’s Arthur Gea 3-6, 6-7 (0/7), 7-6 (9/7), 7-6 (7/3), 6-4 in a match lasting five hours and 13 minutes.
Gauff
Van de Zandschulp is back in the quarterfinals for the first time since 2021, although he made waves in 2024 with a second-round upset of Carlos Alcaraz.
