4. B.J. Penn
History will remember at least two things about B.J. Penn: he was the greatest lightweight in the history of MMA and that he sought to prove, unlike any other fighter, that he was the greatest pound-for-pound fighter in the history of MMA.
After picking up much of his boxing technique in street fights as a child and earning in black belt in Brazilian Jiu-Jitsu and winning the BJJ black belt World Championship in just three years, Penn made his way into MMA at only 22 years old. Penn, one of the few fighters in the post-tournament era of the UFC to make his MMA debut with the UFC, is known as “The Prodigy.” Never has a fighter had a more appropriate nickname.
The list of opponents whom Penn has beaten reads like a who’s who of Mixed Martial Artists: Din Thomas, Caol Uno, Matt Serra, Takanori Gomi, Matt Hughes, Renzo Gracie, Joe Stevenson, Sean Sherk, Kenny Florian, and Diego Sanchez. Penn became the youngest fighter to receive a UFC title shot at 23 years, 29 days old, facing Jens Pulver for the lightweight title. Penn lost the fight but earned another shot a mere 13 months later, following Pulver’s departure from the UFC. In the finals of the UFC’s lightweight title tournament, Penn fought Uno, whom Penn had previously beaten in just 8 seconds, to a five-round draw that led to the lightweight title remaining vacant for over four years.
Penn would go on to challenge and defeat Matt Hughes for the UFC welterweight title during the prime of Hughes’ career in one of the great upsets in the history of the sport. Penn would eventually win the UFC lightweight title on his third attempt by beating Joe Stevenson. Penn subsequently defended the title more times (3) than any lightweight champion in UFC history before losing the title to Frankie Edgar this past March. Edgar is the only lightweight whom Penn has fought and not beaten.
Those his victories have made for a stellar career, Penn’s losses are almost as significant. Penn’s career has spanned five weight classes — lightweight through heavyweight. His decision loss to Lyoto Machida – a match in which Penn ballooned up to 191lbs. against Machida’s 220lbs. – is an almost unfathomable testament to Penn’s talent and desire to compete against the best across all weight classes. Penn’s fights against both Hughes and St. Pierre are some of the most memorable inUFC history. Though Penn has just one win in the four fights, Hughes and St. Pierre are the only two men to stop Penn in 22 career fights.