Jon Jones could not believe what he had just witnessed. Olympic gold medalist, Gable Steveson, suffered his first professional mixed martial arts (MMA) loss last night (Sat., Sept. 19, 2026), getting knocked unconscious by MASSIVE betting underdog, Sean Sharaf, just 12 seconds into their UFC 331 main card clash from inside Crypto.com Arena in Los Angeles, California, Sharaf needed only one clean combination to pull off the staggering upset. Indeed, “The Smoke” landed a picture-perfect, one-two combination that immediately switched off Steveson’s lights, sending one of UFC’s most heavily-hyped prospects crashing to the canvas (watch highlights). Jones’ live reaction was almost as memorable as the knockout itself. The former two-division UFC champion — who has served as his coach and mentor — watched the fight unfold ringside and was left completely frozen when Steveson hit the floor. Jones’ mouth dropped wide open as he stared at the screen in disbelief before finally uttering, “Oh my God.” Checkout his stunned reaction below: Jon Jones reaction pic.twitter.com/d0G1EwhLkK — Spinnin Backfist (@SpinninBackfist) September 20, 2026 Jones has been far more than a casual supporter throughout Steveson’s transition into MMA. The pair initially connected when Steveson helped Jones prepare for his 2024 heavyweight title defense against Stipe Miocic. Steveson later joined Jones and his coaching staff in New Mexico, with “Bones” becoming one of the Olympic champion’s primary coaches and mentors. Steveson entered Saturday’s contest with a perfect 4-0 record and was roughly a -2000 betting favorite after stopping all four of his previous opponents. Meanwhile, Sharaf was searching for his first UFC victory after suffering consecutive knockout losses inside the Octagon. Twelve seconds later, Sharaf had completed one of the most shocking upsets in UFC history, while Steveson and Jones were left searching for answers. The most humiliating fraud check in MMA history I bet he quits — Adam Lehrer SOS (@AdamLehrerSP) September 20, 2026 The 26-year-old wrestling phenom remains an absurdly gifted athlete with plenty of time to rebuild, but this was the first major dose of adversity in his young MMA career. Now, Jones will have to help his prized student recover from the exact kind of devastating loss nobody believed was coming. Oh, and to make it worse, Steveson walked out before Bruce Buffer could read the decision, and the Los Angeles crowd let him have it. Gable Steveson and Jon Jones just got booed out of the arena 😬 pic.twitter.com/XgcflQkIKs — Happy Punch (@HappyPunch) September 20, 2026 For complete UFC 331 results, coverage, and highlights click HERE.