You need to see and hear this spinning back elbow knockout. Mexican bantamweight Juan Díaz made headlines on Tuesday night at Dana White’s Contender Series 86, delivering what many are calling one of the most devastating knockouts in the show’s history. The 27-year-old Lux Fight League champion became the first fighter ever to score a spinning back elbow knockout in DWCS history, finishing South Korean veteran Won Il Kwon with just two seconds remaining in the second round.​

Spinning Back Elbow Knockout

The knockout itself left viewers across social media stunned, with many commenting on the audible impact of the strike. Fans reported hearing the elbow connect from across the arena, with one observer noting it “sounded like the crack of a Kendo Stick in WWE.” The sharp crack of bone meeting skull reverberated through the UFC Apex, creating an instantly viral moment that caught the attention of ESPN’s SportsCenter.​

Díaz, who entered the fight with a 14-1-1 record and an eight-fight winning streak, had been studying his opponent throughout the bout. The Peruvian-born fighter, who fights out of Tijuana, Mexico, demonstrated patience and tactical awareness before capitalizing on Kwon’s tendency to duck his head during exchanges. In a post-fight interview, Díaz revealed he had been practicing the spinning elbow technique in every striking session, stating he attempts the move whenever he sees an opening.​

Won Il Kwon, nicknamed “Pretty Boy,” brought significant credentials to the matchup. The 30-year-old South Korean had competed in ONE Championship for six years, where he achieved nine knockout victories and once challenged for the ONE Bantamweight Championship. Kwon entered DWCS following a first-round TKO loss to Fabrício Andrade in his most recent ONE Championship bout earlier in 2025. Despite being favored by bookmakers at roughly 6-to-4 odds, Kwon found himself on the wrong end of a highlight-reel finish that will likely define both fighters’ careers.

The spinning back elbow has emerged as 2025’s most devastating trend in mixed martial arts. Earlier this year, Lerone Murphy shocked Aaron Pico’s UFC debut with a similar technique at UFC 319, while Diego Lopes earned a $100,000 bonus for his spinning elbow knockout of Jean Silva at Noche UFC in September. Carlos Prates also scored a spinning elbow knockout against Geoff Neal on the same UFC 319 card, earning both fighters Performance of the Night bonuses.

Dana White’s visible reaction to Díaz’s finish highlighted the significance of the moment. The UFC president, known for his animated responses to spectacular knockouts, was seen standing and smiling in disbelief as the referee waved off the contest. White later confirmed that Díaz would receive a UFC contract, making him one of five fighters signed from the final episode of DWCS Season 9.

The knockout came at the perfect time for Díaz, who had been building momentum as the bantamweight champion of Mexico’s Lux Fight League. His victory over José Roura in December 2023 to capture the LFL title demonstrated his finishing ability and set the stage for his DWCS appearance. Díaz’s well-rounded skill set, honed through kickboxing and wrestling training from a young age, made him a dangerous opponent for any bantamweight on the regional scene.​

Season 9 of Dana White’s Contender Series concluded with unprecedented violence, breaking the record for most finishes in the show’s history with 36 stoppages across 10 weeks. Díaz’s spinning elbow knockout served as the exclamation point on what many consider the most entertaining season yet, with five fighters earning contracts on the final episode alone.

The aftermath of the knockout saw immediate social media reaction, with the UFC’s official accounts sharing slow-motion replays and celebrating the historic nature of the finish. TikTok videos of the knockout quickly went viral, with fans marveling at both the technique and the audible impact that made the strike so memorable.

The victory also holds special significance for Mexican mixed martial arts. Díaz becomes another Mexican fighter to earn a UFC contract through impressive performances, adding to the country’s growing representation in the world’s premier MMA organization.