LOS ANGELES, CALIFORNIA - SEPTEMBER 19: Gable Steveson reacts after a knockout defeat against Sean Sharaf in a heavyweight fight during the UFC 331 event at Crypto.com Arena on September 19, 2026 in Los Angeles, California. (Photo by Chris Unger/Zuffa LLC) Pump the brakes! Ultimate Fighting Championship (UFC) super prospect and Olympic gold medalist Gable Steveson suffered his first professional loss last night (Sat., Sept. 19, 2026), getting knocked out by Sean Sharaf in just 12 seconds on the UFC 331 main card inside Crypto.com Arena in Los Angeles, California (watch highlights). Nobody saw it coming … except Sharaf. Steveson entered the fight as a ridiculous -2500 betting favorite, while Sharaf was as high as a +1200 underdog at some sportsbooks. The result instantly became one of the biggest betting upsets in UFC history. During the UFC 331 post-fight press conference (watch here), UFC CEO Dana White — who was never entirely sold on crowning Steveson as a future champion before seeing more from him inside the Octagon — reacted to the gigantic upset. “Anything is possible,” White told reporters. “Anything is possible when two guys get in there and start fighting. You never know how fights are going to go. That’s why when people ask me, ‘Is this guy going to fight this guy after Saturday?’ I’m like, ‘Let’s see what happens on Saturday.’ I don’t know what fights are going to look like.” Unfortunately for Steveson, the knockout loss was not the only thing that earned him criticism. The 26-year-old immediately left the Octagon after regaining consciousness, refusing to remain inside the cage for the official result announcement. Numerous fighters and fans blasted Steveson for what they viewed as poor sportsmanship. White, however, did not seem overly bothered by the walkout. “You know, when you’re in that position — obviously, he had huge expectations for himself — it happens,” White said. “F—king Forrest Griffin ran out of the Octagon when he won his fight. These things happen.” Steveson’s perfect record and aura of invincibility were destroyed in only 12 seconds, dropping him to 4-1 as a professional and 1-1 inside the Octagon. The loss does not erase his Olympic gold medal, elite wrestling credentials or extraordinary athletic potential. However, it does expose how little anyone truly knew about Steveson as a mixed martial arts (MMA) fighter. His first four opponents never pushed him beyond the opening round, meaning he had yet to experience any real adversity in the sport. Well, he has now. Steveson is still only 26 years old and has just five professional MMA fights under his belt, so there is plenty of time to recover. How he responds to this humiliation will reveal much more about his future than any of his four dominant knockout victories. Walking out of the Octagon will eventually become a footnote if Steveson rebounds. If he does not, those 12 seconds could be remembered as the moment UFC’s next great Heavyweight hype train completely derailed. For complete UFC 331 results, coverage, and highlights click HERE.