Novak Djokovic's quest for a record 21st major title that would have completed the calendar-year Grand Slam collapsed at the final hurdle with a 6-4 6-4 6-4 loss to Russian Daniil Medvedev in the U.S. Open final on September 12.

Medvedev, playing in his third Grand Slam final, at last hoisted a trophy while avenging a straight sets defeat by Djokovic earlier this year in the Australian Open final.

"Sorry for you fans and Novak because we all know what he was going for," Medvedev said.

"What you have accomplished in your career… for me, you are the greatest tennis player in the history."

Djokovic, the 34-year-old Serb was trying to become the first man in over a half-century to win all four majors (Australian Open, French Open, Wimbledon, U.S. Open) in the same year.

It would have made him only the third man after Don Budge (1938) and Rod Laver (1962 and 1969) to achieve the feat.

"It's a tough one to swallow, this loss, considering everything that was on the line," said Djokovic.

"I was glad it was over because the build up for this tournament and everything that mentally, emotionally I had to deal with throughout the tournament in the last couple of weeks was just a lot. It was a lot to handle.

"At the same time I felt sadness, disappointment, and also gratitude for the crowd and for that special moment that they've created for me on the court."

For the fifth consecutive match, Djokovic found himself in an early hole after dropping the first set.

But this time there would be no way out as the rampaging Russian kept up the pressure with a barrage of aces while allowing Djokovic a single break.

Such was Medvedev's domination that the only tiny bit of drama came late in the third set when the Russian was suddenly hit by a bout of nerves trying to close out the match.

Serving at 5-2 Medvedev double faulted on match point, allowing Djokovic to secure his break.

After the top seed held serve to trim the deficit to 5-4 Medvedev again had match point and again double faulted.

But the 25-year-old did not squander another chance, gathering himself to clinch the title on his third attempt.

Weight of history
Djokovic arrived on Arthur Ashe Stadium court with the weight of history on his shoulders.

An extraordinary women's final on Saturday between teenagers Emma Raducanu and Leylah Fernandez had softened the spotlight's glare on Djokovic but there was no shirking from it on Sunday with tennis fans around the world tuned in to witness history.

The women's final was the first Grand Slam to feature two unseeded players but the men's followed the form book to the letter with number one Djokovic meeting number two Medvedev.

The New York crowd had never really embraced Djokovic the way it wrapped its arms around Swiss Roger Federer and Spaniard Rafa Nadal, who have also won 20 Grand Slam titles.

It had also shown no real love for Medvedev, the lanky Russian who relished the role of U.S. Open villain on his way to the 2019 final.

Perhaps sensing they were about to witness something special, the crowd rallied behind Djokovic from the moment he stepped on court showering him with cheers and chants of his nickname: "Nole, Nole, Nole".

"I felt something I never felt in my life here in New York," said Djokovic. "The crowd made me (feel) very special.

"I did not expect anything, but the amount of support and energy and love I got from the crowd was something that I'll remember forever.

"The emotion, the energy was so strong. I mean, it's as strong as winning 21 Grand Slams.

"That's how I felt, honestly."

But no amount of support could lift Djokovic's game.

The Serb had said he would treat the final as if it were the last match of his career but never came close to his best.

Medvedev was also keenly aware there was a line in the history books for him as well if he were the player to deny Djokovic the coveted calendar year Grand Slam.