Carlos Alcaraz has reached his first grand slam semifinal in historic fashion…

The 19-year-old Spanish tennis player triumphed in a captivating, five-set encounter against Jannik Sinner at the US Open that ended at 2:50 am local time.

It was, by nearly half an hour, the latest ever finish in the tournament’s history.

Alcaraz dropped to the floor and put his hand over his face in disbelief when he sealed match point having come perilously close to defeat in the previous set.

The 6-3, 6-7, 6-7, 7-5, 6-3 victory lasted five hours and 15 minutes – Alcaraz’s second consecutive marathon match after his five-set victory against Marin Cilic in the previous round.

Sinner was serving for the match at 5-4 in the fourth set, but Alcaraz hit back by winning the next three games in a row to force a decider – saving a match point in the process.

Sinner then led by a break in the fifth set, too, only for Alcaraz to once again refuse to bow down.

“This match is insane. I leave at 6am for the airport but I refuse to sleep and miss this,” tweeted American star Coco Gauff.

Alcaraz becomes the youngest men’s grand slam semifinalist since compatriot Rafael Nadal in 2005, and the youngest at the US Open since Pete Sampras in 1990.

“I always say that you have to believe in yourself all the time,” Alcaraz said in his on-court interview. “Hope is the last thing that you lose … I have to stay in the match, trying to stay calm, but it’s difficult to stay calm in that moment.”

Alcaraz will next play another maiden grand slam semifinalist in Frances Tiafoe, the American having defeated Andrey Rublev in his quarterfinal.

Victory means Alcaraz could still become the youngest No. 1 in the history of the men’s rankings next week following top-ranked Daniil Medvedev’s early exit from the tournament.