Serena Williams has a new favorite racket sport called padel, which is a very social doubles sport she calls a mix of "tennis, racketball, and pickleball all in one."

Carmen Mandato, Getty Images

After a legendary career defined by shattering glass ceilings and conquering the court, Serena Williams is trading her tennis strings for a new challenge, a racket-based sport called padel.

Pronounced “paddle” by some enthusiasts and “pah-DEL” by competitors in the professional league called Premier Padel (PPL), the sport has Spanish origins and is huge in Miami, Florida. When I spoke with Williams last month in Miami, she explained why she likes padel so much.

“It’s a racket sport, and clearly I have a connection with racket sports,” Williams said, with a laugh. “I have fun with it. I’m not great yet. I am still discovering the walls.”

Padel combines elements of tennis and squash and is usually played in doubles on a small, enclosed court surrounded by glass and mesh walls that are incorporated into the game.

The four-time Olympic gold medalist and 23-time singles Grand Slam winner was on hand on March 26 at Reserve Padel, a padel club in Miami’s Design District. There, padel enthusiasts can reserve a court or book a round of the popular game with others who share the buzz, on an app called Playtomic.

Of padel, Williams said, “I get a crazy good workout. I’m sweaty, I’m sore. It’s like a mini-tennis. But a very hard version, because it’s intense. You have to have fast hands and good hand-eye coordination. So, it’s really fun.”

On a sun-drenched Thursday afternoon, Williams pulled off the ultimate "pro move," showing up as a surprise to a few groups of unsuspecting players mid-warmup. It was the kind of unexpected entrance only the greatest could make.

VIDEO: Tennis icon Serena Williams drops in on padel players

Beverage brand Heineken 0.0 recently made its debut in padel, which it calls the world’s fastest-growing sport, launching global partnerships with both Premier Padel and Playtomic last month. Heineken 0.0 also announced today that it has brought on tennis icon Williams as its new global brand ambassador, in a major multi-year partnership.

A representative for the Dutch brewing giant explained that the main reason it has gotten into padel as part of its global sports partnerships is that it is an extremely social and collaborative sport.

“At Heineken, we believe the most rewarding moments happen when people stay active, social, and open to new connections, without having to compromise,” said Nabil Nasser, Global Head of Heineken.

“Serena represents that mindset perfectly. Her iconic presence, her confidence, and her love of padel reflects everything Heineken 0.0 stands for: a confident choice for people who want to stay in the game and fully enjoy the social moments around it." Nasser added, "Together, padel becomes a natural way to bring people together—on court and beyond.”

“For me, it’s always about showing up as my best self,” Williams added. Regarding her new partnership with Heineken 0.0, she said it “reflects the kind of intentional choices I make every day. I think Heineken and padel both share that you can make social connections through sport and balance your lifestyle without compromise.”

Williams’ appearance was part of a new feature that Heineken 0.0 calls “Unexpected Doubles,” in which players who book through Open Match by Heineken 0.0 on Playtomic are rewarded for stepping out of their comfort zone with surprise guest appearances.

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Celine Thom, one of the lucky players surprised in Miami, said, “I booked a padel game via Open Match by Heineken 0.0 on Playtomic to meet new people and connect with other local padel players, but I never imagined that I would be playing with the legendary Serena Williams!”

But what was it like for Serena? “It presented a challenge. And I really like a challenge, particularly in a space where I am challenged but not overly challenged, where it’s frustrating. The athletes out there were fun, and none of them were professionals. But I wonder if I could compete with the professionals in padel.”

She added, “I was snowboarding the other day, and I enjoyed that, but I could see myself getting frustrated. As a racket sport, I wasn’t starting from zip zero.”

When I asked Williams if she was good at snowboarding, she conceded, “I’m not terrible.”

Thom added that playing with Williams was “unreal, but having the chance to sit down and connect with her over a beer afterward made it a truly unforgettable experience.”