American decathlete and Olympic defending champion Ashton Eaton is easily one of the best athletes in the world. In Rio, he's competing in 10 events over two days. After Day 1, Eaton was on pace to defend his London gold medal, leading a pack of elite athletes.

The decathlon includes four runs (100 meter, 110 meter hurdles 400 meters and 1500 meter), three jumps (long jump, high jump and pole vault) and three throws (shot put, discus and javelin). The winner of the Olympic title is dubbed the “world's greatest athlete.”

*Business Insider* asked Eaton what is the most athletic sport, and he had this to say:

“I personally believe tennis is the next most athletic sport next to the decathlon. Just because of certain things required. Those matches are three or four hours long. There’s the technical aspect, the agility, the mind-body awareness. Not to mention the game itself is a little bit like a chess match.”

He adds that he thinks there are two parts to athleticism, the body and the mind. Tennis certainly does its part to test the limits of both.

Obviously, comparing the athletic abilities of Novak Djokovic to Lebron James to decathlete champions like Eathon would be a nearly impossible. Rather than open a can of worms, Eaton's answer can best serve as a nod to tennis' impact in the sporting world, and a testament to tennis champions everywhere.

The "world's greatest athlete" will be crowned Thursday night.