"You are one of the strongest women I know," she wrote.
"I was looking at my daughter (OMG, yes, I have a daughter) and she has my arms and legs!
Recent photos show Alexis fast asleep, wearing babygros that read "Smart and strong like my Mama" and "I don't wanna taco bout it".
On her own Instagram page, Serena also wrote a heartwarming letter to her own mother.
It wasn't long ago that she was embroiled in the tabloid drama that comes with associating with none other than Drake.
But there was almost no time to mourn for Serena, because she had met someone new. Since the tennis player and the Reddit co-founder got together, they have been operating in the exact opposite fashion from what we'd come to expect from one of the sports world's biggest stars.
And this time it was a guy that she (and everyone else) could take seriously. They never made an official "we're dating" announcement. In fact, the only reason anyone even knew they were together from the start is on account of their friend's overly chatty tendencies.
Drake and Williams had been friends for quite some time, and at the time of the Great Cincinnati Cuddle-Off E!
News learned that they had been dating for about a month.
In a recent post, she wrote: "Omg Alexis Olympia is snoring. Totally perfect small snore." Last Saturday, she tweeted: "Go out to dinner with friends... She's just so perfect in my eyes." Serena enjoyed a date night with Alexis Baby Alexis is a real cutie, so it's no wonder that proud mum Serena has been showing her off on social media.