Just 10 months after giving birth, and suffering life-threatening complications, Williams will be back in the Wimbledon final on Saturday.
It will be a rematch of the 2016 showpiece against Angelique Kerber that Williams won in straight sets.
This is just a fourth tournament back on tour for Williams, but she has made smooth progress, dropping just one set in her first six matches.
She is just one win away from matching Margaret Court's record of 24 grand slam titles and is chasing an eighth success here.
But the 36-year-old believes she is still finding her way back to her best.
"I was expecting a few more baby steps myself," she said. "But I still feel like I'm in that baby step place.
"I've said it all week, this is only my fourth tournament back. Every time I go out there, I want to take a giant step forward, keep taking giant steps, but keep improving.
"I don't know what I expected from this tournament. I just expected to win a match, then win the next match.
"Whenever I go out there, I just try to win my match. That's literally all I do."
Her toughest test will be waiting in the final as Kerber is getting back to the form that saw her win two grand slams in the 2016 season.
It could have been three had she been able to get the better of Williams in the All England Club final, but the American triumphed 7-5 6-3 in a competitive match.
"It's her second final in three years," Williams added. "That's wildly impressive.
"Believe me, I know she wants to go out there and win. So do I. I think it will be just like the last final, it will be a really good final. Hopefully it will be a good result."
Kerber's form in 2016 saw her end Williams' 186-week stint as world number one, but it went downhill from there for the German.
In 2017 she failed to win a tournament, failed to get past the fourth round at a grand slam and slipped outside the top 20.
But, after pairing up with coach Wim Fissette, she says Williams is not the only one making a comeback.
"I think it is a completely new match," Kerber said. "We both learned a lot. She's coming back. For me also, I'm coming back from 2017.
"It will be a new match. I know that I have to play my best, best tennis to beat her, especially on the grass, on the Centre Court, where she won so many titles here.
"I'm looking forward to playing against her. It's always an honour to be playing against her.
"Serena is one of the best players in the world. We had so many great matches in the last few years. To see her back, it's great."
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