Rafael Nadal won his third US Open and 16th Grand Slam title with a one-sided victory over South Africa's Kevin Anderson in New York.
The world number one powered to a 6-3 6-3 6-4 victory in Sunday's final at Flushing Meadows.
The Spaniard, 31, has now won two Slams in the same year for the first time since 2013, having won the French Open in June.
"It's just unbelievable what happened this year," said Nadal.
"After a couple of years with some troubles, injuries, sometimes playing not good - since the beginning of the season it has been very, very emotional."
The US Open was the last Grand Slam where he was working alongside his uncle Toni, with Carlos Moya taking sole charge of coaching from 2018.
"I can't thank him enough for all the things he did for me," Nadal said of his uncle.
"Probably without him I would never be playing tennis and it's great I had somebody like him pushing me all the time."
The result means this year's major titles are shared between Nadal, at the French and US Opens, and Roger Federer, at the Australian Open and Wimbledon.
Federer remains at the top of the men's all-time Grand Slam list with 19 titles, three ahead of Nadal, who has now won 10 French titles, three US, two Wimbledon and one Australian.
Nadal went into the final with a 4-0 head-to-head record against Anderson, and he dominated once again.
The 2010 and 2013 champion lost just 15 points on serve in the entire match, did not face a break point and won all 16 points he finished at the net.
It was a ruthless demolition job by a man playing his 23rd Grand Slam final, up against an opponent in his first.
Anderson, 31, was the tallest player ever to feature in a Grand Slam final at 6ft 8in, and with a tournament-leading 114 aces was always going to rely on his serve to get a foothold in the match.
The signs were not good, therefore, when he had to fight through six deuces in his second and third service games as Nadal pressed hard.
Anderson clearly felt the need to play to his limits from the outset, attacking the net more than normal to try to keep the points short, but it brought mixed results at best.
The pressure told in game seven when the South African pulled a forehand into the tramlines facing a sixth break point.
Nadal would break again to seal the set with a wonderful backhand drop volley, and Anderson ended the set with just eight winners from 19 trips to the net.
Venus Williams reached her 23rd Grand Slam semi-final with a thrilling win over Petra Kvitova in a final-set tie-break.
The 37-year-old American won 6-3 3-6 7-6 (7-2) in front of a rapturous night-session crowd in New York.
"I was so fortunate to win that match," said Williams. "It came down to the wire and I'm hoping we have more matches like that."
She next faces Sloane Stephens, with all-American semi-finals possible.
Madison Keys and Coco Vandeweghe will try to join their compatriots in the last four when they play their quarter-finals on Wednesday.
"I would love the top four, five to be that [American] again," added Williams. "That would be huge."
Kvitova, 27, missed out on a first US Open semi-final, ending a remarkable run just nine months since she suffered a knive attack at her home, which left her requiring surgery to her playing hand.
"Everything she has gone through is unbelievable," said Williams.
"It's wonderful to see her back and playing. I was so excited to see her playing well, to be able to play her."
Given primetime billing in the opening night-session slot, the match began with errors from both women and ended in a gripping finale.
The pair had met five times before and each time they had needed three sets, twice a final-set tie-break, and once again there was nothing between them.
A weather warning in the second set prompted a delay of 10 minutes as the roof was brought across, and it intensified the atmosphere as the noise built from 23,000 spectators.
Williams gave up the first break of serve at 3-1 with three double faults, before reeling off five straight games as Kvitova racked up the errors.
A loose Williams game early in the second offered Kvitova the lifeline she needed, and she clung on through several edgy service games.
The Kvitova celebratory scream was now regularly reverberating around the stadium as every game seemed to throw up mini-crises - she saved five break points on her way to clinching the set.
Two brilliant cross-court backhands gave Kvitova an early break in the third but Williams recovered from 3-1 down, levelling when the Czech double-faulted.
The scrappy play of earlier was long forgotten as the pair traded service games, with Williams coming through a 10-minute game at 4-4 as Kvitova pressed hard.
It came down to a tie-break and a brilliant return at 1-1 was enough to give Williams the momentum in the decisive shootout.
Roared on by the New York crowd, the 2000 and 2001 champion powered 6-1 clear, enough breathing space to cope with a double fault on her first match point before converting her second.
"I have to say I felt every single one of you guys behind me, all 23,000," Williams told the crowd. "I didn't want to let you guys down."
Maria Sharapova's first Grand Slam tournament in 19 months ended with defeat by Anastasija Sevastova in the US Open fourth round.
Latvia's Sevastova, the 16th seed, won 5-7 6-4 6-2 to reach the quarter-finals in New York.
The 27-year-old will play Sloane Stephens in the quarter-finals, after the American beat Julia Goerges.
Sharapova, ranked 146th after returning from a doping ban in April, was given a wildcard into the main draw.
"It's been a really great ride in the last week," said the 30-year-old.
"I can take a lot from this week. It's great to get that major out of the way. It was an incredible opportunity. I'm very thankful for the opportunity.
"I did my best. I can be proud of that."
The 2006 champion had played just one match since May coming into Flushing Meadows, with injuries forcing her out of the grass-court season and US Open build-up.
She played superbly to upset world number two Simona Halep on the first day of the tournament, and then beat Timea Babos and Sofia Kenin on her way to the last 16.
Sharapova's presence in the main draw divided opinion from the moment her wildcard was announced, but she was unperturbed as she racked up three wins in a row for the first time since her comeback in April.
The Russian was warmly received by spectators and organisers were happy to draw on her star power, putting her on the main Arthur Ashe Stadium for all four of her matches.
That decision was described as "questionable" by fifth seed Caroline Wozniacki, but Sharapova simply responded that scheduling was not her responsibility.
Asked after Sunday's defeat if she felt as though she had a target on her back, Sharapova responded: "I feel like I'm really beyond that. I mean, there's no other way to explain it.
"I think there's only a way to show it on the court, because that's what really matters to me.
"I have so many things in my life that I've already been able to experience, but there's a desire to keep going for more, and to keep training and to keep living through these moments out on these courts.
"That's special and that's meaningful. As long as I have that desire, I'll be there. That's what's important to me."
Venus Williams moved into the third round of the US Open by overcoming France's Oceane Dodin 7-5 6-4.
The 37-year-old hit 33 winners in the first match of day three's night session at Flushing Meadows.
The final match of the day saw fifth seed and two-time finalist Caroline Wozniacki suffer a shock 6-2 6-7 (5-7) 6-1 defeat by Ekaterina Makarova.
Wimbledon champion Garbine Muguruza eased past Ying-Ying Duan in straight sets 6-4 6-0.
Fourth seed Elina Svitolina saw off Katerina Siniakova 6-0 6-7 (5-7) 6-3 and next plays Evgeniya Rodina, who beat Eugenie Bouchard 7-6 (7-2) 6-1.
Sloane Stephens, a semi-finalist in Toronto and Cincinnati, defeated 11th seed Dominika Cibulkova 6-2 5-7 6-3.
Eighth seed Svetlana Kuznetsova,who won at Flushing Meadows in 2004, saved three match points to prevail against Marketa Vondrousova in an entertaining encounter on Grandstand Court.
The 18-year-old Vondrousova was left in tears as she lost the final-set tie-break after struggling with cramp.
Two-time Wimbledon champion Petra Kvitova, seeded 13th, saw off Alize Cornet, who beat Heather Watson in round one, 6-1 6-2.
Fourteenth seed Kristina Mladenovic, who has gone out in the first round in her past three tournaments, continued the pattern as she lost in straight sets to Romania's Monica Niculescu.
American 20th seed Coco Vandeweghe beat compatriot Alison Riske 2-6 6-3 6-4, despite a mixed performance that saw her make 45 unforced errors, while Agnieszka Radwanska registered a 6-4 7-6 (7-3) win over Petra Martic.
Elsewhere, 25th seed Daria Gavrilova, who won her first WTA title at the Connecticut Open earlier this month, beat America's Allie Kiick in straight sets to set up a meeting with Shelby Rogers.
However, 26th seed Anett Kontaveit was beaten 6-7 (5-7) 6-1 6-4 by Czech world number 37 Lucie Safarova.
Five-time champion Roger Federer needed five sets to overcome American teenager Frances Tiafoe in the first round of the US Open.
The 36-year-old Swiss won 4-6 6-2 6-1 1-6 6-4 in his first ever match under the Arthur Ashe Stadium roof.
Third seed Federer goes on to face Slovenia's Blaz Kavcic or Mikhail Youzhny of Russia on Thursday.
Only nine players completed their matches as rain wiped out much of Tuesday's schedule.
Top seed Rafael Nadal beat Serbia’s Dusan Lajovic 7-6 (8-6) 6-2 6-2, before American 15th seed Madison Keys opened the night session with a 6-3 7-6 (8-6) victory over Belgian Elise Mertens.
They benefited from the stadium-court roof, which was not in place when Federer last played at Flushing Meadows two years ago, a knee injury forcing him out 12 months ago.
A crowd of almost 24,000 packed in to see his return to New York, but 19-year-old Tiafoe ensured they saw a far closer contest than expected.
A slow start, first-serve percentage of 54%, and 56 unforced errors were evidence that Federer was well short of his best, but he was happy to come through after a build-up disrupted by a back injury.
He first felt the problem in the Montreal final three weeks ago, and subsequently pulled out of the Cincinnati Masters.
"I was maybe a bit worried from the beginning with my back issue, but eventually I was able to let go," said Federer.
"If I felt that my back was going to get worse every match, I probably wouldn't have played. My hope and belief is that it's only going to get better."
The Swiss has yet to lose a Grand Slam match this year, having won his 18th and 19th major titles in Australia and at Wimbledon, while skipping the French Open.
Few expected Tiafoe, the world number 70, to trouble him greatly, but in a match where errors far outstripped winners, amid wild swings of momentum, the teenager ran him close.
Asked how he felt at the end of the match, Federer said: "Extremely well. To get through a five-setter you have to be OK.
"It's going to give me great confidence in the body and in my game, because preparation was a little bit compromised, so I'm really, really happy with tonight."