The first set was decided by a tie break, in which Osaka was clearly dominant, winning 7-1.
Brady, who did not drop a set up till the semi-final stage, came roaring back in the second set. She took it 6-3.
The deciding set saw the 4th seed Osaka breaking Brady to go 3-1.
She never faltered henceforth as she closed the set 6-3, for another final match.
Her opponent will be either Belarusian Victoria Azarenka or Naomi’s 2018 foe, 38 year-old Serena Williams.
Osaka had walked out for her semi-final match in Arthur Ashe Stadium in a Philando Castile mask, to highlight racial injustice in America..
For each match, she wore a different face mask, on which is etched the name of a Black American victim of police brutality.
In round one, she wore the mask for Breonna Taylor, the 26 year-old killed by police in her apartment.
In round 2, her mask was for Elijah McClain, killed in Colorado.
In the quarter-finals, she came in with George Floyd mask, the 46 year-old asphyxiated by policemen in Minneapolis, whose death triggered global demonstrations of Black Lives Matter.