An up-and-coming UFC athlete has challenged Rafa Nadal to a fist-fight

• Rafa Nadal better watch his back.
• Rafael Fiziev, who collected the biggest UFC win of his career Saturday, wants Nadal next.

LAS VEGAS — Tennis great Rafa Nadal better watch out.

The 22-time Grand Slam winner was forced to withdraw this week from his Wimbledon semifinal against Nick Kyrgios because of an abdominal injury, according to the BBC.

But the 36-year-old might have more concerning issues in the near future as he was on the receiving end of a fighter's call-out in the UFC.

Rising MMA star Rafael Fiziev scored the most significant win of his entire career Saturday when he finished legendary lightweight fighter Rafael dos Anjos in the fifth round of an event Insider attended at the Apex in Las Vegas.

Having cleared one Rafa out from combat sports, Fiziev said he wants to dispose of another Rafa so that he himself can be known as the best Rafa in all sports.

"Now I want to say, we know who is the best Rafa in the UFC," Fiziev said in a post-fight victory speech you can watch here.

"So now I want to challenge to find out who is the best Rafa in sport — Rafa Nadal! Come here!"

Fiziev doesn't like that Nadal is 'named Rafael'

Speaking backstage after his win, Fiziev elaborated on the challenge when speaking to Insider.

"I hear about him a long time but I never see him in life, for real. Of course, everyone knows this guy," Fiziev told us.

When we asked what Nadal had done to him to deserve a call out from him, Fiziev said: "He's named Rafael."

He added: On how a UFC fight in an Octagon could be fairer for Nadal, Fiziev said the first, second, third, and fourth rounds could all be tennis. "Round five — MMA."

Fiziev then laughed.

It's wildly unlikely Fiziev will ever fight Nadal.

A likelier bout to transpire could be one involving Justin Gaethje, as Fiziev stared down media camera lenses during his post-fight press conferences to say how serious he is about competing against the American.

Prior to his victory over dos Anjos, Fiziev was in 10th place in the UFC's lightweight rankings.

Following the knockout victory, he could end up leapfrogging dos Anjos into seventh place, instead.