Canadian superstar Bianca Andreescu famously wrote herself an imaginary winner's cheque for the US Open as a child, the sum of which was in no small part thanks to the Original 9, led by Billie Jean King.

"Every year, I'd look at the prize money and, understanding the sacrifice that went into ensuring it was equal to the men's earnings, it gave me that much more drive to continue to work towards my dream of winning the US Open," Andreescu wrote in an open letter commemorating the 50th anniversary of the Original 9.

She ultimately won the cheque along with the US Open trophy last summer, storming through the a memorable fortnight that ended with a win over 23-time Grand Slam champion Serena Williams, and credits King and the Original 9 with helping her get there.

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"Even with the odds stacked against you, the nine of you had enough faith in yourselves and each other to sign $1 contracts with magazine publisher Gladys Heldman, another trailblazing woman in her own right, to compete in a tournament where the risk was losing your tennis careers.

"Your dreams were much bigger than rankings and Grand Slams. You set out to make sports, and in turn the world, a better, more equal place for women. Your goals were clear: That any girl from anywhere would have a place to compete. That women would be recognized for their accomplishments, not only their looks. And that they would be able to make a living playing professional tennis."

The 20-year-old not only thanks the Original 9 for the strides they made towards equality, but also for the voices and platforms she and colleagues like Naomi Osaka and Coco Gauff have to speak out on behalf of causes that matter to them.

"With your experiences as an example, the next generation - my generation - of young women is taking charge, using our platforms to speak out for what we believe in and putting it all on the line, regardless of what the outcome or reaction will be. Your leadership has created a powerful platform foundation for us all to speak up for ourselves."

Click here to read Andreescu's full letter, published on BBC Sport Tennis.

Original 9: Celebrating 50 Years