Andy Murray has pulled out of his Washington Open quarter-final on Friday after only finishing his last-16 win at 03:02 local time earlier the same day.
The 31-year-old Briton, playing in his third tournament after hip surgery, was due to play Australian Alex de Minaur.
The former world number one broke down in tears after beating Romanian Marius Copil in the early hours of Friday.
Murray has also withdrawn from next week’s Rogers Cup in Toronto to continue his recovery.
The Scot says he will now focus on preparing for the Cincinnati Masters, which starts on 13 August.