"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," Williams continues.
"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!
"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.
"Thank you for being the role model I needed to endure all the hardships that I now regard as a challenges--ones that I enjoy. I hope to teach my baby Alexis Olympia the same, and have the same fortitude you have had.
"Promise me, Mom, that you will continue to help. I'm not sure if I am as meek and strong as you are yet. I hope to get there one day. I love you dearly.
Your youngest of five,
Serena"
The tennis star announced via social media last that she gave birth to a girl named Alexis Olympia Ohanian Jr.
Williams wrote Wednesday that their daughter was born on Sept. 1 and weighed 6 pounds, 14 ounces. One posting also says about the newborn, "Grand Slam Titles: 1."
Williams won her 23rd Grand Slam singles championship at the Australian Open in January - while she was pregnant.
She has not competed anywhere since but has said she intends to return to competition by next year's Australian Open, which starts on Jan. 15, 4½ months after her baby was born.
"If she's ready, she'll play. If she's not, she won't play. I'm not a doctor. I can't decide when she's going to be ready to practice. If we can have enough practice so she can be ready, she'll play," Patrick Mouratoglou, Williams' coach, said last weekend at the U.S. Open.
"I don't want her to go compete if she's not ready," Mouratoglou said. "I told her: 'You come if you're ready.' And I will do everything for her to be ready for Australia. But if she is not ready, of course she won't compete."