Australia's Alex de Minaur is in the semi-finals of the Citi Open without a fight after Andy Murray pulled out of their quarter-final.
Murray's decision came after he won a trio of three-setters and was a victim of a schedule that had him start his latest victory at midnight, not long after he has returned from an 11-month injury layoff.
De Minaur was given a walkover into the semi-finals of the hard-court tuneup for the US Open.
Murray's third-round victory over Marius Copil ended just past 3am on Friday.
"Finishing matches at three in the morning is not good. It's not good for the players. It's not good for anyone, I don't think, involved in the event. It's not good for fans, TV. Nobody," said Murray, a former No. 1 who had an operation on his right hip in January.
"I'm giving my view right now as someone who's just come back from a very, very long injury layoff.
I don't think I should be put in a position like that ... I don't think it's reasonable," Murray said.
Asked after beating Copil how his body is holding up, Murray replied: "It doesn't feel great, just now."
"I don't know how you are expected to recover from that. By the time you're done with all your recovery and stuff, it's going to be 5:30, 6 o'clock in the morning.
"It's not good. And it's basically like playing two matches in a day."
He also announced on Friday that he was going to skip next week's Toronto Masters.
Meanwhile, defending champion Alexander Zverev made his way to the semi-finals by coming back for a 3-6 6-1 6-4 victory over No. 7 seed Kei Nishikori in a rain-interrupted match on Friday.
Top-seeded Zverev also eliminated 2015 Washington champion Nishikori at this event a year ago en route to the title.
On Saturday, he'll face 19-year-old Stefanos Tsitsipas of Greece. The No. 10 seed beat No. 3 David Goffin 6-3 6-4.
Tsitsipas is coming off his first run to the fourth round at a grand slam tournament, last month at Wimbledon.
