The Japanese star lost the opening set inside half an hour but turned things around brilliantly to triumph 1-6 6-3 6-3 and claim her third grand slam title.
Here, the PA news agency looks at the story of the penultimate day of action in New York.
Picture of the day
Tweet of the day
Stat of the day
Osaka's comeback marked the first time in 26 years the women's final in New York has been won by the player who lost the first set. The last woman to achieve the feat was Arantxa Sanchez Vicario, who defeated Steffi Graf in 1994 having also dropped the opening set 6-1.
Mariah Carey hits Flushing Meadows
In this most strange of years, opening the women's final with Mariah Carey sitting in a car inside the Billie Jean King National Tennis Centre and singing to footage of the greats of women's tennis made perfect sense. Maybe.
Dominic Thiem will look to make it fourth time lucky in grand slam finals when he takes on first-time finalist and good friend Alexander Zverev for the men's title.