We all know Caroline Wozniacki is a total badass on the tennis court, but turns out she’s just as fierce in the boxing ring. 

In a recent profile for Esquire, Wozniacki said she loves boxing to tone her amazing arms and core, and that she used to train with an actual professional boxer. Not one to be intimidated by another athlete’s prowess—the former No. 1 ranked tennis star has faced off against the best players in the world—she once landed a punch on her partner’s face so hard he instinctively struck back to protect himself. How’s that for hitting like a girl? 

Unfortunately, Caroline ended up on the losing end of that bout when her partner popped her in the nose.

“I went down pretty fast,” Caroline said. “Our coach was yelling, ‘Get up and hit him!’ I’m rolling around on the floor thinking, Okay, I may be done with this now.”

• MUST SEE: These 10 GIFs show exactly why we’re obsessed with Caroline Wozniacki

Though she decided to give up sparring, Caroline is back to training for tennis and will grace the courts with her beauty and general badassery at the Rio Olympics this summer.

Bonus: See Caroline’s best moments in BODY PAINT for SI Swimsuit 2016!