Jessica McCaskill tells her younger self to keep striving for success in a message recorded for the DAZN network .
McCaskill defeated Cecilia Braekhus for the second consecutive time in their rematch on Saturday night, retaining her position as the undisputed welterweight champion.
Scores of 110-89, 99-90 and 98-91 summed up what a dominant display it was for the the 36-year-old American, who had suggested before the fight that she would be sending her opponent - who also wrote a similar letter - to an inevitable retirement.
She starts the letter to herself saying, “Girl, you are something else. Just like your hero Flo Jo, you are never going to fit any cookie-cutter mould, and you know what? It’s OK to be different, Jess.
“To do your own thing. To do many, many, many things.”
McCaskill was raised by her great aunt, and at times the family had to live in a local church, tough times that McCaskill hints at.
“I don’t feel I’m writing this letter to a child because real soon you’re going to have to take on stuff only adults should,” she writes.
“Remember these moments because one day you’ll use them to help millions of other girls who look up to you for inspiration.”
McCaskill started a career in investment banking, before ultimately swapping paths to become one of the greatest boxers in the women’s sport so far, turning professional in 2015.
“There is a great stage waiting for you, not the theatre that you love nor the churches that Mom preaches at, but the ring, under the brightest lights, the biggest venues, the most glamorous crowds.
“Those shoes on your feet will have to last you a long time but keep walking your own path, and one day, you’ll be able to afford new shoes every day.
“The journey you’re on is going to be bumpy. It’s not going to be pretty, but that’s just the way you’ll like it.”