Alexander Zverev took the first step in his mission to defend his title on a night shift in Acapulco.

At 4.55 a.m. local time, the German number one made it through to the round of 16 with a hard-fought 3:6, 7:6 (12:10), 6:2 first round win against the American Jenson Brooksby – no match at tour level has ever been that late ended.

"I'm happy that I won and am part of history," said Zverev after the memorable game: "It was an incredible fight, an incredible match.

I hope there will be many more to come this week.”

Oscar Otte retired

The previous record was set by Lleyton Hewitt (Australia) and Marcos Baghdatis (Cyprus) in 2008 at the Australian Open with an end at 4:34 a.m.

Zverev's match in Mexico only started shortly after 1.30 a.m. local time, as the two previous matches in the evening session had each broken the three-hour mark.

Olympic champion Zverev, who had to fend off two match balls in the second set, now meets Peter Gojowczyk from Munich after his success.

Gojowczyk, who slipped into the main draw as a lucky loser, beat Brandon Nakashima (USA) 6-4, 6-4.

On the other hand, Cologne's Oscar Otte was eliminated after losing 6-2, 6-4 to Spaniard Pablo Carreno Busta (No. 8).

Zverev acted cautiously in the first set against Brooksby, who had made a big leap in the world rankings last year, and his opponent attacked with strong returns.

In the second round it was a balanced match at a high level, in which Zverev needed extremely strong nerves.

Then, at a late hour, the match developed more and more in the direction of Zverev, which the German number one still won after 3:20 hours.