1. B.J. Penn
Penn was the first American to ever claim Mundials gold in the black belt division and accomplished the feat in 2000 after just three years of formal jiu-jitsu training. Soon after, “The Prodigy” brought his electrifying talents to the Ultimate Fighting Championship and forever altered the mixed martial arts landscape. Penn christened his MMA career with three straight first-round finishes, as he bested Joey Gilbert, Din Thomas and Caol Uno in a six-month span and proved he was far more than a one-trick pony. A majority decision loss to Jens Pulver in his fourth professional appearance cost him the UFC lightweight championship and cooled some of the hype around him. His work ethic, motives and drive were all questioned. However, even in defeat, the sense of awe that always seemed to accompany Penn never fully dissipated. The proud Hawaiian remains one of only three men to win UFC titles in two divisions: He won the welterweight championship with a stunning upset submission against Matt Hughes at UFC 46 in January 2004 and claimed the vacant lightweight crown with a blood-soaked tapout against Joe Stevenson at UFC 80 four years later. Penn has competed in five different weight classes, from 145 pounds to heavyweight, but he did his best work as a lightweight. While some view his underwhelming 16-11-2 career record as a disappointment, eight of those 11 defeats were to former UFC champions: Hughes, Pulver, Frankie Edgar (three), Georges St. Pierre (two) and Lyoto Machida.
The Sherdog Top 10 series is voted upon by a panel of Sherdog.com staff members: Jordan Breen, Tristen Critchfield, Mike Fridley, Brian Knapp and Mike Sloan.