Dan Henderson is something of a legend in MMA. In a career spanning nearly 20 years, the former Olympic wrestler has beaten some of the best in the world, including Antonio Rodrigo Noguiera, Renzo Gracie, Vitor Belfort, Wanderlei Silva, Fedor Emelianenko, "Shogun" Rua, and Rich Franklin--many of them after his 40th birthday. And though he was never able to win a UFC title (losing first to Anderson Silva at middleweight and “Rampage” Jackson at light heavyweight), Henderson was such a big name for the organization that he was picked to coach against Michael Bisping on The Ultimate Fighter: United States vs. United Kingdom in 2009.

With his subdued personality, however, Dan was an odd fit for reality TV, and he only reluctantly played the straight man to Bisping's antagonistic heel. Over the course of the taping, a strong resentment grew between the two men, and by the time they fought at UFC 100 on July 11, 2009, that resentment had blossomed into hatred.

On the night of the fight, Bisping looked sickly and rumors of a bad weight cut began to circulate, but that didn’t stop Dan Henderson from being Dan Henderson. For a round and a half, he stalked Bisping calmly and deliberately, repeatedly throwing leg kicks and jabs, always looking for his famed overhand right.

Bisping, normally known for his cardio and boxing skills, seemed uncertain and continually circled to Dan's dangerous right side. Between the first and second rounds Bisping’s cornermen were furious, screaming about his footwork and demanding that he focus on the fight. But the second round played out much like the first, with Henderson wading forward and Bisping unable to mount a counterattack. Halfway through the round, Henderson once again closed the distance, setting Bisping up with a left leg kick and a jab fake. Bisping dropped his guard and attempted to parry the jab, leaving himself wide open for Henderson’s legendary overhand right.

The knockout, when it came, was cinematic, ripping Bisping's head 90 degrees, rendering him unconscious instantly, and sending him falling straight backwards. Fueled by anger, Henderson literally dove on Bisping with one final (if unnecessary) punch. The drama of the moment and the severity of the knockout would make this the go-to highlight reel moment in Dan's storied career.

While fighters are instructed to continue going for a finish until stopped by the ref, the images of Henderson leaping through the air fist first and of an unconscious Bisping being attended to afterwards by the ring doctor, the ref, and cutman "Stitch" Duran are stark reminders of the risks fighters take on behalf of the fans.

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