1. Georges St. Pierre (19-2)
The popular Canadian has his detractors, but no one can argue with his results. Following a shocking knockout loss to Matt Serra at UFC 69, St. Pierre made the necessary adjustments and never again tasted defeat.
“Rush” regained the Ultimate Fighting Championship welterweight crown in his rematch with Serra at UFC 83, punishing him with a series of gruesome knees to the body on the ground. From there, St. Pierre denied all challengers, besting Jon Fitch, B.J. Penn, Thiago Alves, Dan Hardy, Josh Koscheck, Jake Shields, Carlos Condit and Nick Diaz.
St. Pierre’s last successful title defense came in a contentious split decision over four-time NCAA All-American Johny Hendricks at UFC 167 on Nov. 16, 2013. Shortly after, the Tristar Gym cornerstone announced he was vacating the championship to take a break from mixed martial arts. To this day, St. Pierre remains on the sidelines, even as rumors swirl about his possible return. That he still sits atop this list, nearly three years since he last fought, serves as a testament to his greatness.