Novak Djokovic will return to the top of the world rankings after an emphatic late-night victory in the first round of the US Open on Monday.
Second seed Djokovic, who was forced to miss last year's US Open over Covid-related travel restrictions and therefore has no ranking points to defend, eased to a 6-0, 6-2, 6-3 win against France's Alexandre Muller in just one hour and 35 minutes.
The win means Djokovic is guaranteed to replace defending US Open champion Carlos Alcaraz as world No 1 when the tennis rankings are next updated after the tournament.
Entering Arthur Ashe Stadium after 11pm local time, Djokovic began like a player determined to get off the court as quickly as possible.
Djokovic, a three-time US Open champion, reeled off the opening eight games before Muller belatedly got on the board, earning sympathetic applause from a crowd including former US President Barack Obama and his wife, Michelle.
The 36-year-old Serb, chasing a record-extending 24th male Grand Slam title, will face Spain's Bernabe Zapata Miralles in the second round.
"I didn't care if I started after midnight because I was looking forward to this moment for a few years, to be out on the biggest stadium in our sport, the loudest stadium in our sport, playing night session," Djokovic said. "It was a great joy to be stepping out on the court.
"I think the performance explains how I felt tonight, particularly in the first two sets. It was kind of lights-out tennis really, almost flawless, perfect first set.
"Overall I'm very, very pleased with the way I feel, with the way I'm playing. Hopefully I can maintain that level."
Gauff grinds past Siegemund
Djokovic's arrival on court had been delayed after a gruelling three-set battle between American teenager Coco Gauff and Germany's Laura Siegemund in the preceding night game.
The 19-year-old Gauff, tipped by many as the biggest threat to defending US Open champion Iga Swiatek, was forced to dig deep before winning 3-6, 6-2, 6-4 in 2hr 50min.
An ill-tempered clash was marked by tetchy confrontations by both players with chair umpire Marijana Veljovic.
Gauff accused the Serbian official of failing to properly enforce time violation rules against Siegemund.
"I felt like the rules were being bent," Gauff said. "That's why a lot of players get mad when these time violations are called because one ref is letting them go over, the other is more strict on the time."
Siegemund, 35, meanwhile voiced disgust at the partisan New York crowd, describing them as "respectless" for the way they cheered every error or missed first serve.
"They had no respect for me, no respect for the way I played, no respect for the player that I am, they had no respect for good tennis," Siegemund said.
Swiatek storms into second round
In other women's matches on Monday, defending champion Swiatek needed less than hour to defeat Sweden's Rebecca Peterson 6-0, 6-1.
The 22-year-old world No 1 from Poland overwhelmed her opponent with five breaks of serve and 20 winners to complete victory in just 58 minutes on the Arthur Ashe Stadium.
"I wanted to start the tournament with everything I was focusing on. I was happy to play a great game, with all the pressure and expectations I was happy on the court," said Swiatek after her win.
Swiatek, targeting her fifth Grand Slam title, will face Daria Saville of Australia in round two.
While Swiatek advanced safely, there was no such luck for Greece's eighth seed Maria Sakkari, who became the highest ranked early casualty, beaten 6-4, 6-4 by Spain's Rebeka Masarova, ranked 71st in the world.
Kazakhstan's fourth seed Elena Rybakina was an easy winner over Ukraine's Marta Kostyuk, cruising through to the second round with a 6-2, 6-1 victory.
Wozniacki wins on return
There was also a win for former world No 1 Caroline Wozniacki, making her first Grand Slam appearance in over three years.
The 33-year-old Danish mother-of-two, who came out of retirement earlier this month, defeated Russian qualifier Tatiana Prozorova 6-3, 6-2.
Back in the men's draw meanwhile, Djokovic's route to a potential final meeting with Alcaraz was made easier as Danish fourth seed Holger Rune was stunned in four sets by Spanish journeyman Roberto Carballes Baena, a clay-court specialist ranked 63rd in the world.
Carballes Baena punished an error-strewn display by Rune to win 6-3, 4-6, 6-3, 6-2.
Last year's US Open runner-up, Norway's fifth seed Casper Ruud, reached the second round with a battling 7-6, 3-6, 6-4, 7-6 defeat of Emilio Nava of the United States.