The 36-year-old turned out alongside sister Venus in a doubles clash against the Netherlands at the Fed Cup in North Carolina on Sunday, just five months after giving birth to daughter Alexis Olympia Ohanian.
She was born weighing 6lbs 14oz on 1 September, and joined her 23-time Grand Slam champion mother at her wedding to Reddit co-founder Alexis Ohanian in Rome only 11 weeks later.
Williams had set herself an ambitious comeback target of defending her Australian Open crown in January, but decided she was not quite feeling up to it a week before the tournament began.
And despite falling to a straight-sets loss to Demi Schuurs and Lesley Kerkhove on Sunday, the greatest player of her generation showed glimpses of her prowess in front of a sellout crowd in Asheville.
“I honestly feel better than I thought I was going to feel,” she said.
“I feel like I didn’t expect to play, you know, like that for me. I feel like I’m on the right track. I didn’t know what to expect. Maybe that’s why I felt like I did better.
“I didn’t expect to have that much power on my serves, even though they didn’t go in. It’s just a start. I feel like that’s a very good step in the right direction.”
The loss was of no consequence to the US team, who had already won three matches in the best-of-five tie to progress to the semi-finals against France in April, but it was a useful workout for Williams as she continues to get used to parenthood.
Williams was left bedridden for six weeks due to a series of complications with Alexis’ birth, including a pulmonary embolism that led to multiple surgeries, with her daughter delivered by emergency cesarean section.
Williams said: “This is literally my first time travelling with the baby and everything. I’m going to try to do better. I’m always going to have the best and highest expectations for myself.”
The next opportunity for Williams to add to her record-setting Grand Slam haul is the French Open at Roland Garros in late May, which she withdrew from last year due to her pregnancy.
Despite having not played a competitive singles match since last year’s Australian Open final, which she won, she is still ranked 22 in the world by the Women’s Tennis Association.