Alex de Minaur is in the semi-finals of an ATP tournament for the first time after Andy Murray pulled out of his Citi Open quarter-final against the Australian.
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.
De Minaur was given a walkover into the semifinals of the hard-court tuneup for the US Open.
Murray’s third-round victory over Marius Copil ended just past 3am on Friday.
He also announced on Friday that he was going to skip next week’s Toronto Masters.
Murray said in a statement on the ATP website: “I won’t be able to play my match tonight. I’m exhausted after playing so much over the past four days, having not competed on the hard courts for 18 months.
“I also need to be careful and to listen to my body as I come back from a long-term injury.”
Murray is working his way back into form after having surgery on his right hip and being sidelined for 11 months.
Meanwhile, Greek teenager Stefanos Tsitsipas eliminated No. 3 seed David Goffin 6-3 6-4 on Friday to reach the semis.
The 19-year-old Tsitsipas is coming off his first run to the fourth round at a grand slam tournament, last month at Wimbledon.
He will face No. 1 seed Alexander Zverev or No. 7 Kei Nishikori, both past champions in Washington, in the next round.
The quarter-final between Zverev and Nishikori is in a third-set rain delay.