The 36-year-old, who will be facing Angelique Kerber in the final on Saturday 14 July, told the BBC her win "wasn't inevitable."
"It's no secret I had a super tough delivery," she said, after her win. "I lost count after, like, four surgeries because I was in so many surgeries. There was a time I could barely walk to my mailbox.
"I was expecting a few more baby steps... Again, I've said it all week, this is only my fourth tournament back."[But] every time I go out there, I want to I guess take a giant step forward, keep taking giant steps, but keep improving."
Williams previously wrote about her traumatic birth in an article for CNN, "I almost died after giving birth to my daughter, Olympia," she wrote. "My daughter was born by emergency C-section after her heart rate dropped dramatically during contractions."
As a professional tennis player, Williams has managed to get back into sport relatively quickly after giving birth, but of course this isn't the same for all mums.
Previously speaking to HuffPost UK Laura Gray, 28, from Diss in Norfolk, said she found that getting back into running was more of a gradual process than she had anticipated after she had her daughter.
"My first run I could barely manage a mile before my body said enough was enough," she said. "I hurt all over and in places I thought wasn't possible. I had to stop and this made me feel like I would never be as fit as I was previously. I had to fight these thoughts."
Zoe Colver, 39,from Manchester, said she was shocked about how long it took her to get back into playing hockey. "Physically I was surprised just how much of my core strength I had lost," she said. "Doing a plank was near impossible at the start but I'm getting better now."
To new mums, her message was simple: "There is no rush to get back to it, start gently with walking and work up to anything more strenuous."