Novak Djokovic won a record-equalling 24th Grand Slam singles title by outlasting Daniil Medvedev in a punishing US Open final in New York.
The 36-year-old Serb won 6-3 7-6 (7-5) 6-3 but the straight-set scoreline does not tell how deep he had to dig.
A comfortable opening set was followed by a brutal second which lasted one hour and 44 minutes.
After the pair exchanged breaks early in the third, Djokovic took control to level Margaret Court's 50-year record.
"It obviously means the world to me," said Djokovic on winning his 24th major.
"I'm really living my childhood dream to compete at the highest level in this sport, which has given me and my family so much from difficult circumstances.
"I never thought I would be here but the last couple of years I thought I had a shot at history. Why not grab it when it is presented?"
Second seed Djokovic looked physically troubled in that gruelling second set, but showed all the hallmarks of his greatness to win a fourth US Open title.
Djokovic, who surpassed Rafael Nadal's record tally of 22 men's major titles earlier this year, has matched Australia's Court at the second attempt after losing the Wimbledon final in July.
He has won three of the four Grand Slam titles in 2023, becoming the first man to achieve this feat on four occasions.
Now the incoming world number one has the chance to surpass Court at January's Australian Open - where he has already won a record 10 titles.
It felt fitting that Djokovic set up championship point by winning another lengthy rally and, after being made to wait to serve by shouts from the crowd, sealed victory when Medvedev hit a forehand into the net.
"I would definitely sign right away the paper if somebody would tell me I would win three out of four and play Wimbledon finals this year," Djokovic said.
"There is a little regret that I didn't win that Wimbledon final. But, at the end of the day, I have so much more to be happier and content with than actually to regret something."
Djokovic shows again why he can never be written off
When Djokovic lost to 20-year-old Carlos Alcaraz in the Wimbledon final it felt like a changing-of-the-guard moment in the men's game.
But, even in the twilight of his career, Djokovic continues to show he can never be written off.
Djokovic has won eight of the past 12 majors he has played at and will replace Alcaraz again as the world number one on Monday.
"It's not my interest or business to really review what everyone talks about or thinks, whether there is a passing of the torch, or whatever you want to call it, happening or not happening in the sport," he said.
"I focus on what I need to do and how I get myself in an optimal state so that I can win the biggest trophies in our sport. That's what I care about."
Djokovic was dialled in from the start of Sunday's final, playing patiently and precisely to break for a 2-0 lead, with Medvedev looking ragged as he fell 3-0 behind.
With Medvedev deep behind the baseline when receiving, Djokovic smartly decided to serve-volley on his way to 4-1 - a tactic he employed throughout - and showed his all-round quality to close out the opening set.
Djokovic had only lost from a set up at the US Open once on 73 previous occasions, against Switzerland's Stan Wawrinka in the 2016 final.
Djokovic's relentless returning continued to draw mistakes out of Medvedev, who was serving poorly and making loose errors, at the start of the second set.
The constant pressure led to another break point for Djokovic in the seventh game, but Medvedev hung on to hold as Djokovic tumbled on to the court after an energy-sapping 31-shot rally.
Something appeared to be troubling Djokovic physically as he held a long game for 4-4 and survived Medvedev's first break point of the match.
The Russian third seed was sticking longer in the rallies now, pushing Djokovic to his limits and creating a set point at 6-5 which the Serb saved with another serve and volley.
But Djokovic eventually got over the line to ensure a marathon set would be settled by a tie-break.
Medvedev led 5-4 when a stunning 23-shot point eventually went his way despite Djokovic's doggedness, only for the veteran to lock in again and win the next three points for a two-sets-to-love lead.
It was clear to see Medvedev had needed to level by taking that second set to stand any real chance of victory and the feeling of the inevitable was heightened by the Russian needing treatment on a shoulder injury before the third set.
He offered resistance by putting it back on serve at 3-2, but Djokovic broke again immediately and confidently clinched another famous win.
How Djokovic celebrated historic number 24
After shaking hands with his opponent, Djokovic sobbed as he knelt on the court before picking out his daughter Tara from the crowd.
Further tears followed as he went to celebrate with his nearest and dearest, which included parents Srdjan and Dijana, wife Jelena, son Stefan - and Hollywood actor Matthew McConaughey.
Addressing his family, Djokovic thanked them for all their "sacrifices" when he was a child growing up in war-torn Serbia in the 1990s.
"The odds were pretty much against me and my family. It was not accessible, not affordable, but I fell in love with tennis," he said.
"No-one in my family played tennis but [there was] incredible resilience and belief from my family.
"My wife, my kids, my team, this is your trophy as much as it is mine."
Djokovic also pulled on a T-shirt which paid tribute to NBA legend Kobe Bryant, his friend who was killed in a helicopter crash in 2020 and wore 24 in his playing days.
"Kobe was a close friend, we chatted a lot about the winners' mentality when I was struggling with injury and trying to work my way back to the top.
"He was one of the people I relied on the most, he was always there for support in the most friendly way.
"His passing hurt me deeply and 24 is the jersey he wore at Lakers so I thought it would be nice to acknowledge him."
'Incredible moment' for 'super-human' Djokovic - analysis
The New York crowds were treated to two special nights after Coco Gauff won a maiden Grand Slam women's singles title on Saturday at the beginning of her exciting career but Djokovic's triumph brought emotion for different reasons, with the Serb nearing the end of his.
BBC pundits hailed Djokovic's achievement with former British number one Annabel Croft saying fans had witnessed "something incredibly special".
"We witnessed him tying Margaret Court with 24 titles. It has taken him a time to get there but he's done it. He's super-human isn't he?" she said on BBC Radio 5 Live.
"He had to put himself through the pain barrier to be able to do it. I don't think Medvedev could have played any better. I just admire the strength of character he has but to find the layers he found in his game. It was perfection."
American former player Jeff Tarango hailed an "incredible moment" that "no-one will ever see again".
"I don't think any other human could have done what he did in this second set and be able to able to stumble through it, fall over many times and come back again, and again and again.
"This was a kid who grew up playing tennis in an empty swimming pool and he became the greatest tennis player of all time. You can try to psychoanalyse all you want but the fact is he has put all the pieces of the puzzle together. He can't get any better."