Emma Raducanu has completed her New York fairytale and one of the most astonishing feats in sport by beating Leylah Fernandez to win the US Open.
Playing in just her second grand slam tournament, the 18-year-old Raducanu overcame 19-year-old Fernandez 6-4 6-3 to become the youngest major champion since a 17-year-old Maria Sharapova won Wimbledon in 2004.
Raducanu did not drop a set through qualifying and the main draw to become the first British woman to win a grand slam singles title since Virginia Wade lifted the Wimbledon trophy in 1977.
Fernandez is only two months older than Raducanu having celebrated her 19th birthday earlier this week but the Canadian, who had claimed a host of big scalps, including defending champion Naomi Osaka, had no answer to the brilliance of the Briton on Saturday.
Raducanu's achievement is unprecedented.
No qualifier had ever reached a slam final before while she is the first woman ever to win a title in as few as two tournaments.
While her Wimbledon breakthrough showed she could potentially be a grand slam winner in the future, no one, least of all the teenager herself, expected it to come so soon.
Simona Halep acknowledged the achievement on Twitter, describing the feat as "extraordinary".
UK Labour MP Dr Rosena Allin-Khan said Raducanu's achievement is truly remarkable migrant story.
The evening in Flushing Meadows began with a ceremony to remember the victims of the September 11 attacks 20 years ago - before both finalists were born.
The reception the young women received when they walked out onto Arthur Ashe indicated that Fernandez, who lives in Florida, would receive the most support, her giant-killing run having captured the hearts of the New York crowd.
Raducanu had not been troubled enough to really need to draw on the crowd, with her closest set coming in the second round of qualifying, when she was just another lower-ranked hopeful trying to reach the main draw.
She shut down any suggestion there might be any pressure on her going into the final.
It certainly did not appear that way as she swung freely through the first game, clinching it with a cross-court backhand struck so true that Fernandez did not move.
This was a very different scenario for Fernandez, who had been the big underdog in her previous four matches but here found herself as the higher ranked and more experienced player.
Leylah Fernandez hugs Emma Raducanu after Raducanu defeated Fernandez in the women's singles final of the US Open tennis championships. Source: AAP
This quickly became an almighty battle, Raducanu breaking for 2-0 on her sixth chance only for Fernandez to take her fourth opportunity to hit straight back.
It was a showcase of all the skills, mental resilience and athleticism that had seen the two women conquer all before them.
The Raducanu return has been arguably the shot of the tournament and two sizzlers brought up two set points in the 10th game.
Fernandez saved both, and a third that followed, but on the fourth Raducanu drilled a forehand down the line before raising her arms and letting out a huge 'Come on'.
Raducanu has been more contained emotionally than her opponent throughout the fortnight but this was the most pressure she had been under and she knew what a huge moment it was in the match.
Fernandez knew, too, and Raducanu had three chances to break for 2-0 in the second but the Canadian dug in brilliantly to hold and then surged ahead with a break in another long game.
But back came Raducanu with more superb returning and a run of four games in a row took her to the brink of victory.
Emma Raducanu of Great Britain reacts after defeating Lelyah Fernandez of Canada to win the women's final match. Source: AAP
She held two match points at 5-2 but Fernandez was not finished, saving both and then forcing a break point as Raducanu attempted to serve it out.
To add to the tension, the British player was forced to take an injury timeout after grazing her leg sliding to a ball, much to the annoyance of Fernandez.
Raducanu saved the break point, and another, before bringing up her third match point.
And this time she took it - with an ace - to secure the trophy and $2.5 million ($A3.5m) winner's cheque.
