Novak Djokovic defeated Daniil Medvedev in straight sets on Sunday to win his fourth US Open and a record-equalling 24th Grand Slam singles title, cementing his claim as the greatest tennis player in history.

The 36-year-old Djokovic won 6-3, 7-6 (7/5), 6-3 to become the oldest men's champion in New York in the Open era and match Margaret Court's all-time mark for most Grand Slam victories.

"I don't know where to start. It obviously means the world to me," said Djokovic, wearing a white jacket with the number 24 on his chest during the trophy presentation.

"It's hard to describe. I'm really living my childhood dream to compete at the highest level in this sport.

"I never imagined I would be standing talking about 24 Grand Slams but the last couple of years I've felt I have a chance and I have a shot at history and why not grab it."

The Serbian is the first man to win three Grand Slam events in the same season four times, crowning his impending return to world number one in the most fitting of ways inside Arthur Ashe Stadium.

The victory added to his wins at the Australian and French Opens earlier this year, with the only blemish his five-set defeat to Carlos Alcaraz in the final of Wimbledon in July.

"You know, some people who are born, he's a genius. He's one of kind. Not too many people in this world like him in sport-wise," said Djokovic's coach, Goran Ivanisevic.

"This is one of the biggest achievement in the sport history."

Medvedev suffered his fourth loss in five Grand Slam finals, all of which were against Djokovic or Rafael Nadal.

"First of all I want to ask Novak: What are you still doing here? Come on!" quipped Medvedev.

"I don't know when you are planning to slow down a little bit.

"I mean, 24. I feel like I have not a bad career and I have 20 titles. You have 24 Grand Slams. Wow."

Medvedev defeated Djokovic in straight sets in the 2021 final to prevent the Serbian from becoming the first man to win all four Grand Slams in the same year since Rod Laver in 1969.

Djokovic admitted to feeling overwhelmed on that occasion, but there was little evidence of nerves as he quickly took command of Sunday's championship match.

The second seed -- who missed last year's US Open because of his refusal to be vaccinated against Covid-19 -- burst out of the gate with a confident hold sealed by successive aces and struck at the first opportunity, punishing Medvedev for a double-fault to break for a 2-0 lead.

A third ace consolidated his advantage before Medvedev got on the board in the fourth game.

The pair traded holds largely untroubled until Djokovic again put pressure on Medvedev as the third seed served down 2-5.

Medvedev dug in to twice stave off set points, but Djokovic calmly made the set his the following game.

- Second set grind -

Medvedev dethroned last year's champion Alcaraz with a "12 out of 10" performance in the semi-finals, but he struggled to replicate his very best consistently against an imperious Djokovic.

Attempting to be the first player to beat the top two seeds en route to the title since 1975, Medvedev once more repeatedly found himself under the pump early in the second set.

He was able to resist, hitting a sweeping volley to fight off break point as he secured a gutsy hold for 4-3 before finally asking questions of Djokovic, who was showing signs of fatigue.

A leaping overhead gave Medvedev his first break chance of the contest the very next game, but Djokovic responded with a brilliant scoop on the half-volley to save it.

Djokovic wobbled serving at 5-6, double-faulting twice as Medvedev brought up set point. But Djokovic was waiting as Medvedev went cross-court, and put away the volley to force a tie-break.

Medvedev seemed to have the momentum on his side after winning an astonishing rally to nose 5-4 ahead only for Djokovic to bag the next three points, snatching a marathon 104-minute second set and closing in on a historic triumph.

"Should have won it," Medvedev said of the second set. "Should have won it, but sometimes tennis is not that easy."

Djokovic sportingly offered to help Medvedev to his feet after the Russian took an awkward tumble early in the third set, but there was no such goodwill when two break points came about soon after.

Medvedev pumped a backhand long to hand Djokovic a 3-1 advantage. He gave the break straight back, but Medvedev faltered again and there was no mistake second time around as Djokovic wrapped up the title before the emotions streamed out.

- Not setting any limit on Grand Slam titles

Novak Djokovic said he plans to play as long as possible while he is still capable of competing for the biggest prizes after winning a record-equalling 24th Grand Slam title at the US Open on Sunday.

Half of Djokovic's Grand Slam triumphs have come since he turned 30. The Serbian has also won seven of the past 10 majors he has entered.

"I'm going to keep going. You know, I feel good in my own body. I still feel I got the support of my environment, of my team, of my family," said Djokovic.

"Grand Slams... have been always the highest goal and the priority of mine in the whole season.

"I don't play as much in terms of other tournaments, so I try to, you know, prioritise my preparation so that I can peak in Slams."

"Knowing that I play at such a high level still and I win the biggest tournaments in this sport, yeah, I don't want to get rid of this sport," said Djokovic.

"I don't want to leave this sport if I'm still at the top, if I'm still playing the way I'm playing."

- No numbers in mind -

Djokovic admitted there are times he questions his future in a sport he has dominated for well over a decade.

"Occasionally asking myself, why do I need this still at this stage after all I have done, you know? How long do I want to keep going? I do have these questions in my head, of course," he said.

But his habit of setting himself increasingly lofty goals as his career has progressed means there are few thoughts of calling it a day any time soon unless his body dictates otherwise.

"I don't put any number right now in my mind on how many Slams I want to win until the end of my career. I don't really have any number," said Djokovic.

"I'll continue to prioritise them as my most important tournaments and where I want to play the best tennis.

"So that will not change. That will stay the same in the next season or I don't know how many more seasons I have in my legs. So let's see."

His coach Goran Ivanisevic joked that Djokovic's unquenchable thirst for success could see him carry on until the 2028 Olympic Games in Los Angeles.

He also said there was little chance Djokovic would hang up his racquet if he won next year's Australian Open to claim the outright record with a 25th Grand Slam crown.

"He just enjoying, he likes the challenges. Like you ask me 25, yeah, if he wins 25, he's going to think, If I win 25, why not 26? It's always one more, something more."