But the former UFC light heavyweight champion considers Jon Jones the best.
Rua fought Jones at UFC 128 in March. Rua was dominated the entire fight, losing by TKO in the third round.
Shogun has beat UFC greats Mark Coleman, Chuck Liddell, Lyoto Machida and Quinton “Rampage” Jackson. Rua has also defeated current Strikeforce Heavyweight Champion Alistair Overeem twice.
But Rua told ESPN that Jones was the toughest.
“After the Jon Jones fight I gave it a lot of thought, I reflected a lot, I thought about my training…everything. I came to some conclusions, but I don’t want to take anything away from Jones, he’s a good fighter.
I have given it a lot of thought because I hope to fight him again one day.”
Despite beating both Lyoto Machida and Quinton "Rampage" Jackson in the past, Rua will have to wait in line for a title shot.
Although it's something he doesn't want to do, he knows it is "a part of the game." Rua's climb to the top begins with the first man he ever faced in the UFC, Forrest Griffin.
Despite being heavily favored to win, Rua lost the fight by rear naked choke.
Rua will have a chance to avenge that lost and get back on top in his home country of Brazil, at UFC 134.