After giving birth to daughter Alexis Olympia Ohanian Junior earlier this month, the 35-year-old tennis champion wrote of now seeing life through her mother's point of view, and asked her to promise to "continue to help."

After declaring her mother as "one of the strongest women I know," Williams went on to compare the physical likeness she shares with her newborn.

"She has my arms and legs! My exact same strong, muscular, powerful, sensational arms and body," Williams wrote, still marvelling that she also now has a daughter.

While the letter was a public celebration of her mother, Williams also addressed the barrage of body-criticism she has faced in her career. Such as the times that people have likened her strong physique to that of a man, and false accusations that her performance on the court was a result of drugs.

Williams stressed that the harsh public criticism she has dealt with since her teenage years is something she never wants her daughter to have to endure. While she hasn't explicitly addressed tennis rival Maria Sharapova's critical description in her new memoir Unstoppable: My Life So Far, it has been noted that Williams appears to reference statements made in the book.

"I don't know how I would react if she has to go through what I've gone through since I was a 15-year-old and even to this day," she wrote.

"I've been called a man because I appeared outwardly strong. It has been said that that I use drugs (No, I have always had far too much integrity to behave dishonestly in order to gain an advantage), It has been said I don't belong in women's sports - that I belong in men's - because I look stronger than many other women do. (No, I just work hard and I was born with this badass body and proud of it)."

Speaking to the positive influence of her mother, particularly as a African-American woman, Williams also wrote of hoping to pass on that confidence to her own daughter.

"But mom, I'm not sure how you did not go off on every single reporter, person, announcer and quite frankly, hater, who was too ignorant to understand the power of a black woman," she wrote.

"I am proud we were able to show them what some women look like. We don't all look the same. We are curvy, strong, muscular, tall, small, just to name a few, and all the same: we are women and proud!"

The champion credited her mum with helping her "endure all the hardships" before signing off with a compliments for her "meek" and "strong" mother, including her desire to follow her same path through the challenges of parenthood.

"You are so classy, I only wish I could take your lead. I am trying, though, and God is not done with me yet. I have a LONG way to go, but thank you."

"I hope to teach my baby Alexis Olympia the same, and have the same fortitude you have had."

Williams' first child, named after her Reddit co-founder fiance Alexis Ohanian was born on September 1, and weighed 3.12 kilograms.