1) Jon Jones (18-1-0)
Jon Jones has crushed the best of the light heavyweight division and humiliated his former training partner, Rashad Evans, in a one-sided decision. The only blemish on his record is a ridiculous disqualification loss to Matt Hamill.
Notable victories: Rampage Jackson, Lyoto Machida, Shogun, Rashad Evans
2) Jose Aldo (22-1-0)
The Brazilian featherweight buzzsaw has not been beaten in eight years. He recently proved who the toughest man under 170 lbs. was when he topped former lightweight king Frankie Edgar. This victory, and his desire to finish fights, make him a close second to Jon Jones.
Notable victories: Frankie Edgar, Urijah Faber, Mike Brown, Mark Hominick
3) Georges St-Pierre (24-2-0)
GSP has lost his killer instinct over the years, not finishing a fight since 2009. However, his high fight IQ and strategic brilliance are still enough to keep him on top of the welterweight food chain.
Notable victories: Matt Hughes, Carlos Condit, Josh Koscheck (twice), B.J. Penn
4) Anderson Silva (33-5-0)
Sheer hubris has caused the best fighter of all time to take a tumble down the current P4P rankings. While he will probably climb back to the top of the mountain in December, Silva is never going to live down the most embarrassing loss of his entire career.
Notable victories: Chael Sonnen (twice), Vitor Belfort, Dan Henderson, Rich Franklin (twice)
5) Demetrius Johnson (17-2-1)
The fastest fighter in the world has nearly perfect technique, a huge gas tank, and an insane work ethic. His submission victory over Moraga earlier tonight proves that.
Notable victories: Joseph Benavidez, John Dodson, John Moraga
6) Cain Velasquez (12-1-0)
He was the second fighter to ever finish Minotauro Noguiera, smashed the monstrous Brock Lesnar in the first round, and avenged his only loss by giving Junior Dos Santos a five-round beatdown. Need I say more?
Notable victories: Junior Dos Santos, Brock Lesnar, Minotauro Noguiera
7) Renan Barao (32-1-0)
He hasn't lost in years and has, in all likelihood, permanently spoiled the UFC's plans to make Urijah Faber bantamweight champ. Dominick Cruz has his work cut out for him when he comes back from injury.
Notable victories: Urijah Faber, Scott Jorgensen, Michael McDonald
8) Frankie Edgar (15-4-1)
The ultimate underdog has a granite chin and neck of steel. He has avenged one of his losses by finishing Gray Maynard and another one was a razor-thin decision dropped to Jose Aldo. The first of his two "losses" to Benson Henderson was questionable at best. The second one was highway robbery.
Notable victories: BJ Penn (twice), Gray Maynard, Sean Sherk
9) Chris Weidman (10-0)
The undefeated New Yorker handed Anderson Silva his first ever KO loss. We'll find out if he can do it again in December when Silva treats him with the respect that he deserves.
Notable victories: Anderson Silva, Demian Maia, Mark Munoz
10) Ronda Rousey (7-0)
The Muhammad Ali of women's MMA has torn through all of her opposition so far with only an armbar. The fact that she can do it even though they are expecting it means that she will be moving up this list very quickly.
Notable victories: Miesha Tate, Sarah Kaufman, Liz Carmouche