World number three Alexander Zverev defeated Jenson Brooksby in three sets at the Mexican Open in a first-round contest which set a new record for the latest finish to a tennis match.
Defending champion Zverev won 3-6 7-6 (12-10) 6-2 with the match ending at 4:55am local time in Acapulco.
A marathon second set was clinched by the German in one hour and 51 minutes.
The previous latest finish was 4:34am when Lleyton Hewitt beat Marcos Baghdatis at the 2008 Australian Open.
Play in Acaplulco does not begin until 6pm local time because of the heat and humidity, and all three of Monday's Centre Court matches lasted more than three hours.
The three hour 20-minute match between Zverev, 24, and 21-year-old American Brooksby - which did not get under way until 1:35am - fell one minute short of the longest match in Mexican Open history.
That record had been set earlier on Monday, when Stefan Kozlov defeated 2014 champion Grigor Dimitrov 7-6 (10-8) 5-7 6-3.
John Isner and Fernando Verdasco also came close to rivalling that time, as Isner prevailed 7-5 6-7 (4-7) 7-6 (7-3) after three hours and 14 minutes.
Zverev will face compatriot Peter Gojowczyk next, on Wednesday.
'The latest entry in tennis scheduling's hall of shame'
BBC tennis correspondent Russell Fuller
There is always a ghoulish fascination when a sporting event finishes late into the night.
An impressively sized crowd stayed to the end, supplemented no doubt by a few extra viewers in Europe, where the match could almost said to be taking place in prime time.
But this is not clever. Or unusual. It the latest entry in tennis scheduling's hall of shame.
Yes, it is hot and humid in Acaplulco. But trying to schedule three matches from 6pm invites trouble and almost guarantees play will sometimes extend into the early hours.
Usually, these matches will be played in virtually empty stadia, and it is just not fair on the players.
As Johanna Konta said after a 3am finish at the 2019 Australian Open: "I don't agree with athletes having to physically exert themselves in the wee hours of the morning - I think it is quite dangerous."