Stephan Bonnar, who helped launch the UFC into the mainstream with his fight against Forrest Griffin in the finals of the first season of "The Ultimate Fighter" reality show, died at age 45, the promotion announced Saturday.
Bonnar died of presumed heart complications while at work, according to the UFC.
Bonnar and Griffin were both inducted into the UFC Hall of Fame in 2013. Their knockdown, drag-out fight on April 9, 2005, is regarded as one of the most important fights in the history of the promotion. "The Ultimate Fighter" reality series and that fight in particular were critical to landing and keeping the UFC on cable.
The drama of Griffin vs. Bonnar, with both men digging deep in a bloody brawl, has long been an example of what the sport of MMA can be, allowing it to form its own identity separate from other combat sports such as boxing. Griffin won the fight via unanimous decision to earn a six-figure UFC contract. But the fight was so good that UFC president Dana White awarded Bonnar a contract, as well.
"Stephan Bonnar was one of the most important fighters to ever compete in the Octagon," White told UFC.com on Saturday. "His fight with Forrest Griffin changed the sport forever, and he will never be forgotten. The fans loved him, related to him and he always gave them his best. He will be missed."
Bonnar, a native of Hammond, Indiana, but a longtime resident of Las Vegas, had not fought in MMA since a bout with Tito Ortiz under the Bellator banner in 2014, which headlined what at the time was the most watched Bellator event in its history. Bonnar last competed in the UFC in 2012, a loss to all-time great Anderson Silva. Before that bout, Bonnar was on a three-fight winning streak.
After his loss to Griffin in "The Ultimate Fighter" finals, Bonnar also went on a three-fight winning streak before falling to Rashad Evans, who would go on to become UFC light heavyweight champion. Griffin and Bonnar competed in a rematch of their classic fight in 2006, with Griffin winning again via unanimous decision. Griffin would also go on to win the UFC light heavyweight belt.
In his career, Bonnar faced seven future or former UFC champions: Griffin, Ortiz, Silva, Evans, Jon Jones, Lyoto Machida and Mark Coleman. Bonnar named his first son Griffin after his most significant rival, who went on to become a good friend.
Bonnar, who finished his career with a 15-9 record, also did color commentary over the years for the WEC promotion and worked several times as an MMA analyst for ESPN and Fox Sports.
Following his MMA career, Bonnar took up professional wrestling and made multiple appearances with Impact Wrestling in 2019.