Serena Williams’ vaunted comeback at Wimbledon this week did not go according to plan. The 23-time Grand Slam winner lost Tuesday in a first-round shocker to World No. 115 Harmony Tan. 

That stunning early departure in London, after nearly a year of being off-court, opened the floodgates for the usual question posed to the 40-year-old superstar: When will you retire?

Asked at a post-match press conference if she’ll ever play tennis again professionally, Williams cryptically said, “That’s a question I can’t answer. I don’t know . . . Who knows? Who knows where I’ll pop up?”

The reality, actually, has little to do with swatting a furry yellow ball. Williams, who Forbes estimates is worth $260 million and made $45.9 million last year in off-court income, is popping up everywhere: in Hollywood, fashion, publishing, venture capital and more. She has laid the groundwork for a post-sports career that could rival Michael Jordan’s.

Sports business writer Andrew Petcash has even predicted Williams will become the first female billionaire athlete, thanks to her portfolio of endorsements and investments, including a minority stake in the Miami Dolphins — an NFL team valued at $3.42 billon.

“She’s not just an endorser, she’s a mogul,” Bob Dorfman, a sports marketing expert with the Pinnacle agency, told The Post. “With the big-name athletes, you’re seeing a lot more of them becoming business people and business owners and running businesses — not just pitching products.” 

In Williams’ case, she has already gone from the baseline to the boardroom.

In March, the four-time Olympic gold medalist unveiled Serena Ventures, her venture capital company that invests in promising new startups. It has already raised more than $111 million for 60 some companies, including money transfer service Sendwave and online learning platform MasterClass.

“I’ve always been fascinated with technology and I’ve always loved how it really shapes our lives,” Williams told the New York Times back then. “When I met my husband [Reddit co-founder Alexis Ohanian], that was our first conversation. That’s how we met. I was talking about investments.”

Williams, who wed Ohanian — who Forbes estimates is worth $70 million — in 2017, also serves on the boards of Poshmark and SurveyMonkey. 

Plus, she’s right at home in Hollywood.

While fans didn’t watch Williams in any Grand Slam final over the past 12 months as she recovered from an injury, they did get to see her holding court on the red carpet, including in a rose-colored Gucci gown at the Oscars — about 25 miles away from where she grew up in Compton, California.

Serena and Venus Williams were producers on “King Richard,” the Best Picture nominee about their father Richard Williams. And they had the best seat in the house for Will Smith (who won Best Actor for playing her dad) slapping presenter Chris Rock.

She recently told Insider that “King Richard” could be just the big-screen beginning, and she could be involved in more films about the legendary careers of her and her sister, who are only kids in the movie.

“ ‘King Richard’ had a perfect ending with Venus on the tennis court,” she said. “Venus goes in her direction, and I go in my direction. It’s two completely different stories.”

“I would think she would stay in the entertainment field and try and do more with movies,” Dorfman said. “Along the lines of LeBron James, who has his SpringHill Company. Steph Curry is doing the same thing.” 

Williams is way ahead of James and Curry when it comes to fashion. She’s been making waves with her outfits for decades — rocking eye-popping tutus and catsuits during matches, or couture at the Met Gala. She turned her love of clothes into a moneymaker in the 2010s with three collaborations for HSN. When one debuted at New York Fashion Week in 2016, Williams sat front row next to tennis buff Anna Wintour. 

Then, in 2019, she launched a retail collection of her own, S by Serena, which focuses on sustainably made, budget-conscious clothes. On the website, she models many of the looks herself. Williams also has a cosmetics brand called Aneres and her own jewelry line.

Williams became a mom in 2017, when daughter Alexis Olympia Ohanian was born, and she’s being a parent has inspired her new artistic endeavors. 

After the proud mom started posting Instagrams of her tot with her doll, Qai Qai, the toy exploded on social media — the doll’s dedicated account has amassed 337,000 followers — and became the launchpad for Williams’ first children’s book, “The Adventures of Qai Qai,” out Sept. 27. It’s about a little girl who finds confidence with the help of a magic doll. 

With her interest in children, Dorfman said Williams might consider opening a tennis school for kids who have less access to the sport. (The Venus and Serena Williams Tutorial/Tennis Academy in Los Angeles was not founded by the sisters.) 

All that said, Williams has not officially retired, and her losing match on Tuesday still marked a significant improvement from her loss due to injury at the 2021 Wimbledon. The next slam, the US Open, begins Aug. 29, and Williams has not announced if she plans to play it yet. She is still one slam away of tying Margaret Court‘s record of 24 wins.

Whatever happens, Williams has plenty to look forward to when she puts down the racket.

“She’s such a huge name, even if she’s not playing, she’ll still be a big face in the sports world,” Dorfman said. “Even outside the sports world, she’s got icon potential.”