Emma Raducanu will seek to become the first British woman to win a Grand Slam singles title in 44 years when she takes on fellow teenager Leylah Fernandez in an unlikely US Open final between two players who have lit up New York.
A final between the world numbers 150 and 73 was never predicted, nor should it even be as thrilling a prospect as it is, but this US Open - and these two players - have defied expectations at every turn.
Raducanu's story is the stuff of dreams - ranked too low to make the main draw, the 18-year-old had to come through three rounds of qualifying and has become the first qualifier to reach a major final.
And she did all that without dropping a set.
Fernandez, 19, has brushed aside a series of leading players - taking out defending champion Naomi Osaka, fifth seed Elina Svitolina, world number two Aryna Sabalenka and three-time Grand Slam champion Angelique Kerber.
Their different paths and contrasting styles - but similarly fearless approach - have set up the first Grand Slam final between teenagers since the 1999 US Open when Serena Williams beat Martina Hingis.
A maiden major beckons for one of them but regardless of whose name is etched onto the trophy, they have both shown there is a bright future for tennis at a time when fans were wondering who might fill the void when the sport's biggest names eventually retire.
'Whole country will be cheering Raducanu on'
Raducanu's exploits have drawn praise from royalty, politicians and rock stars, as well as pundits and fans.
If she finally ends the country's wait for a first female Grand Slam singles champion since Virginia Wade's 1977 Wimbledon triumph, someone might have to invent some new superlatives as they have all been used to describe her already.
What has been impressive is that not only is she 18, but she has clinically beaten much more experienced players such as Olympic champion Belinda Bencic and 17th seed Maria Sakkari with a fearless game that shows great variety, as well as the intelligence to change tactics on the spot.
And then there is that smile.
So relaxed has she appeared at times that she has managed to beam between points, and the mega-watt grin that has lit up the Arthur Ashe Stadium after converting match points has won over local fans as well as those back home.
She has already achieved so much in just three months, reaching the last 16 at Wimbledon on her Grand Slam debut, rising from 338 in the rankings to just outside the top 30 when they are next published on Monday, and she will also become British number one.
"When you see that kind of talent, that won't be denied," 18-time Grand Slam singles champion Martina Navratilova said.
"She is almost like the finished product, when she is just getting started."
British fans will be relieved the final is at a much more palatable time of 21:00 BST, with many having set their alarms for the middle of the night when she played her semi-final.
"The whole country will be cheering you on in the final," Prime Minister Boris Johnson tweeted.
Emma Raducanu's road to the finalSimilar backgrounds, different styles, same goals
Of course Fernandez, who is just two months older than Raducanu and turned 19 this week, has been living her own dream at Flushing Meadows.
She, too, has been showered with congratulations, and among the messages from the prime minister and top sports people, there was this bit of advice from Canadian ice hockey captain Marie-Philip Poulin: "Make sure to have that maple syrup before the final!"
Fernandez's matches have been stickier affairs than Raducanu's, with four of her six matches going to three sets and featuring five tie-breaks. The Briton, by contrast, has not dropped a set or faced even a tie-break.
But Fernandez's opponents have been bigger names and her demeanour on court is also different to Raducanu's.
The left-handed Canadian loves fist-pumping and revving the crowd up to get behind her, while Raducanu cuts a serene figure.
The pair, who were both born in Canada to immigrant parents, have grown up playing in the juniors together, facing each other in the second round of junior Wimbledon in 2018.
Raducanu won that match 6-2 6-4. But so much has changed for both players since then that it cannot possibly be a gauge of what Saturday will bring.
Such is the attention that this match-up is attracting, Novak Djokovic's quest for a record 21st men's major and a calendar Grand Slam has been slightly overshadowed.
"I think we're all just super hungry to make a difference in the tennis world," said Fernandez. "We've always talked about and joked around that we're going to be in the WTA Tour and we're going to be on the big stage together.
"We want to make a difference. We want to make an impact in tennis."
Regardless of the result on in the final, they have certainly done that already.
Leylah Fernandez's road to the final