Sharapova partnered with Mavericks owner Mark Cuban to invest in a fitness company. (Getty)

Maria Sharapova has only been retired from tennis for a few days now, but fans can already get a glimpse of what her second act might look like. 

Sharapova appeared as a guest judge on the business reality show Shark Tank, on the episode that aired on Friday, and she showed herself to be quite a tough businesswoman, turning down many more offers than she accepted. 

But she did outmaneuver the other sharks to make a deal in the show's opening segment, when she partnered with Dallas Mavericks owner Mark Cuban to invest $900,000 for 30 percent of a company called Bala, which makes "wearable weights" fitness bands.  

In another pitch, she chose not to invest in a company called Fur because she wasn't offered a big enough stake in the business. 

"Two-point-five percent is really nothing," Sharapova said. "I feel like I would need so much more skin in the game just to feel passionate about what I'm involved with."

She also rejected a partnership with a "Ping-Pong social club" called Pips & Bounce. "Hellllll no," Sharapova said.

However, she did try out the table for Instagram: 

 
 
 
 
 
 
 
 
 
 
 
 
 

Who wants to be a part of this ping pong party? ???? #SharkTank

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If there's anything we know about Sharapova, she'll take part in numerous other business ventures in the future. Her Shark Tank episode showed us that she also knows how to say no.