3:05 AM ET

The match would not be over. One could say that should not end. Carlos Alcaraz and Jannik Sinner, two of the bright young stars of men's tennis, traded shots of the highest quality and countless momentum swings across five sterling sets for 5 hours, 15 minutes until Alcaraz finally won the last point at 2:50 a.m., The most recent finish in the US Open.

This tournament has produced a tour de force of big cuts on the full sprint and plenty of guts, so it was no surprise that it was as close as it was.

"I'm not sure how I did it," said Alcaraz, who saved a match point in the fourth set.

"Unbelievable" and "amazing" were some of the words he used. There wasn't hyperbole there.

No. 11 Sinner, a 21-year-old from Italy, said that this one would hurt for a long time. Tomorrow I will wake up and try to take away all the positives.

The five-set victory over Marin Cilic ended at 2:30 a.m.. He is the youngest man to reach the US Open semifinals since Pete Sampras won the title at 19 years old. Next week, Alcaraz has a chance to move up to the top spot.

The previous record for the latest time of finish at the US Open was 2:26 a.m. shared by three matches.

You have to believe in yourself all the time according to Alcaraz. The hope is the final thing that you lose.

His victory over Rublev in the quarterfinals ended at 1:45 p.m. When asked about Alcaraz and Sinner, Tiafoe was correct.

"I hope they play a marathon match, super-long match, and they get really tired on Friday," he said with a laugh.

The clock was past 2 a.m. when Coco Gauff, the American who was the runner-up at the French Open, spoke for anyone watching.

Even with thousands and thousands of empty seats, there were enough who remained on hand to make noise. The fans would get louder if the players waved their rackets or motioned with their arms. The fans would respond.

It could have ended in three sets. It was possible to finish in four sets. In five sets, could have finished. The two of us wanted to win. Both of us tried our hardest.

It was always back and forth. It was difficult to list the highlights. One point was won by Alcaraz after he wrapped his racket behind his back and hit the ball. After falling onto his backside, Alcaraz ran to hit a backhand that won the point.

After winning the first set, Alcaraz had five set points in the second.

In the third, Alcaraz broke to lead 5-5 and served for the set, but he was broken to force a tiebreak.

In the fourth, it was Sinner who served for the victory and even came within a point of victory, but Alcaraz broke there and pushed what already was a masterpiece to a fifth.

In the fifth, after a running backhand passing winner that sailed just past Sinner's outstretched arm, Alcaraz put a finger to his ear.

He would serve it out after converting it. The man covered his face with his hand as he dropped to his back.