Britain's Andy Murray demonstrated his grit and guile to frustrate Argentine 24th seed Francisco Cerundolo and start the 10th anniversary of his US Open victory with a first-round win.
Murray, 35, eventually clinched the first set and then raced ahead in the second as Cerundolo became despondent.
The former world number one, who earned the first of his three major titles in New York, went on to win 7-5 6-3 6-3.
The Scot will play Australia's John Millman or American Emilio Nava next.
"It felt like five sets to me, it was tricky conditions, very humid and hot," said Murray.
"But I'm happy with the way I got through that one. He has had a brilliant year, I knew I had to play well and I did that in the important moments."
Murray is one of seven British players competing in the US Open singles and was the first through to the second round after opening play on Louis Armstrong Stadium, which is the second show-court at Flushing Meadows.
Former British number one Kyle Edmund is also playing on Monday as he continues his comeback from a serious knee injury, while 20-year-old Jack Draper - on his overseas major debut - and Harriet Dart will also look to join Murray in earning wins on day one.
Emma Raducanu starts her title defence on Tuesday, with seventh seed Cameron Norrie and Dan Evans also playing on day two.
Murray rolls back years with convincing win
Almost four years on from having major hip surgery, Murray has struggled to string wins together in a season which he recently described as "OK" and wanted "to be better".
Climbing the rankings sufficiently to be seeded for the New York major was the target after Wimbledon, where he lost to 20th seed John Isner in the second round.
Inconsistent performances in North America since did not enable him to achieve his goal and, as a result, the world number 51 ended up being drawn against a seeded player at Flushing Meadows.
While 24-year-old Cerundolo has largely climbed the rankings this year because of his results on clay, it felt like his forehand could cause problems for Murray on the hard court and many predicted a long slog between the pair.
However, that did not play out as Murray ground down his opponent to win his first Grand Slam match in straight sets since Wimbledon in 2017.
Another positive for Murray was there appeared to be no sign of the cramping which he has been hampered by recently, despite the warm conditions which would have been even hotter on the sun-soaked court.
Murray impressed by keeping the pressure on Cerundolo, who became animated between points towards the end of the first set as his head began to drop.
After losing serve in the first game, Murray fought back with four on the bounce and looked increasingly assured in his ball-striking.
Things are often complicated with Murray, though. He suddenly became edgy when serving for the set and a poor game put the opener back on serve.
There was an unusual incident in the ninth game, with Murray leading 5-4, when Cerundolo initially won a point despite a double bounce before sportingly handing it over to the Scot after replays on the big screens showed what had happened.
After sealing victory Murray - who also failed to serve out the second and third sets at the first attempts - thanked Cerundolo for his sportsmanship when they met at the net.