Andy Murray won a deciding-set tiebreak to defeat Marius Copil and reach the Citi Open quarter-finals after an early morning marathon contest in Washington.
After rain forced play to be suspended earlier in the day, both players emerged to a sparse crowd after midnight local time.
Murray, currently ranked world No 832 and playing just his third tournament of 2018, prevailed 6-7 (5-7) 6-3 7-6 (7-4) after over three hours on court and will now meet Australia's Alex de Minaur in the quarter-finals later on Friday, live on Sky Sports.
The first set saw Murray forced to save four break points to bring up a tiebreak, which he appeared to have taken command of by winning the first five points, before Copil hit back by winning seven on the bounce to take the initiative.
But the former world No 1 quickly regained his composure with an immediate break of serve at the start of the second set before a second break of the match ensured the match would go the distance.
With the contest now well into the early hours of the morning, a fired up Murray sought to build on his second set momentum and broke the Romanian to lead 4-2.
His advantage did not last for long as Copil broke back in immediate fashion before both players held their serves to bring up a decisive tiebreak.
After four of the opening six points of the tiebreak went against serve, Murray won three successive points to bring up three match points and secured the win at the second opportunity.
The significance of the victory was clear to see for Murray who, after facing nearly a year on the sidelines with a hip injury, showed his emotion by sobbing in his chair.
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