Third seed Daniil Medvedev overcame a late wobble to hold off a spirited challenge from Argentina’s Sebastian Baez and reach the US Open last 16.
Medvedev, who lifted the title in 2021, took his fourth match point at 01:30 local time to win 6-2 6-2 7-6 (8-6).
The 27-year-old Russian also finished his previous match against Chris O’Connell in the early hours and said finishing so late was “tough”.
“I just want to go to sleep. It’s good we did not finish at 4am,” he said.
“When you go to play at 11pm, it just feels tough. This time I decided not to sleep before and I ate, so I was feeling pretty bad on the court.
“That’s why I was nervous all the match.”
Medvedev will play Alex de Minaur in the fourth round after the Australian 13th seed recorded a straightforward 6-1 6-3 6-2 victory over Chile’s Nicolas Jarry in one hour and 44 minutes.
Italian sixth seed Jannik Sinner knocked out former champion Stan Wawrinka in a 6-3 2-6 6-4 6-2 win.
Sinner, 22 will play Germany’s Alexander Zverev after the 2020 finalist beat Bulgarian 19th seed Grigor Dimitrov in a 6-7 (2-7) 7-6 (8-6) 6-1 6-1 victory.
Russia’s Andrey Rublev also secured his last-16 spot with a 3-6 6-3 6-1 7-5 victory over Arthur Rinderknech of France.
The eighth seed will next face Britain’s Jack Draper, who reached the fourth round of a Grand Slam for the first time with a win over Michael Mmoh.
Draper, 21, is the only remaining Briton in the singles after Cameron Norrie lost to Italy’s Matteo Arnaldi and Dan Evans was beaten by defending champion Carlos Alcaraz.
Victories for Sinner and Spanish top seed Alcaraz mean the pair could face each other in the last eight for a rematch of last year’s quarter-final tie – a five-set thriller won by the Spaniard, which set a record for the latest finish at the tournament of 02:50 local time.
