New York, Sept. 4 -- Alexander Zverev survived another gruelling five-set battle at the US Open, defeating France's Quentin Halys 6-4, 4-6, 7-6(3), 6-7(3), 6-3 to reach the third round on Friday.

The German top seed spent four hours and 33 minutes on court, finishing the contest at 2:15 a.m. local time on a humid night at Flushing Meadows, according to ATP's official website.

It was Zverev's second consecutive five-set victory at this year's tournament after he opened his campaign with a 4-hour, 53-minute win over Lorenzo Sonego.

Despite advancing, the world No. 2 admitted he was far from his best.

"The performance was quite s***, to be honest," said a candid Zverev in his on-court interview. "But I won, and that's the most important ...