Bianca Andreescu of Canada celebrates with the championship trophy during the trophy presentation ceremony after winning the Women's Singles final against against Serena Williams of the United States on day thirteen of the 2019 US Open at the USTA Billie
The 15th seed was repeatedly put under pressure by Williams, who was roared on by a patriotic crowd on Arthur Ashe, but she survived unscathed to come through and triumph in New York.
Williams, seeded eighth, somehow recovered from 5-1 down in the second set to break twice and get back on terms at 5-5 in a quite extraordinary turnaround.
But Andreescu managed to keep her composure despite a raucous crowd and a resurgent legendary opponent to close out a memorable victory.
“I know you guys wanted Serena to win – I’m so sorry!” Andreescu said in an entertaining moment during her victory speech.
"It's so hard to explain (what the win means) in words. I'm just beyond grateful and truly blessed. I've worked really, really hard for this moment and I can't complain. This year has been a dream come true.
"And now to be able to play on this stage against Serena, a true legend of the sport, is amazing."
Bianca Andreescu of Canada celebrates winning the Women's Singles final match against against Serena Williams of the United States on day thirteen of the 2019 US Open at the USTA Billie Jean King National Tennis Center
Image credit: Getty Images
It was a stunning triumph for the 19-year-old from Ontario as she left Flushing Meadows in disbelief at how the American superstar had been left so subdued and outplayed.
Andreescu has become the first Canadian to win a Grand Slam singles title and the first Canadian woman to win a major in the professional era.
Amazingly, the title marked her first appearance in the main draw at Flushing Meadows - and the first teenage champion of the event since 2006.
In defeat, a gracious Williams, who has been beaten in four Slam finals since claiming her last major title at the Australian Open in 2017, was prevented from equalling Margaret Court's record of 24.
"Bianca played an unbelievable match," she said.
"Congratulations, I'm so proud and happy for you. I wish I could have played better."