At the end of the year, Akebono had his mixed martial arts debut against Ultimate Fighting Championship pioneer Royce Gracie at K-1 Premium 2004. The bout was not easy to negotiate, as Royce demanded it to be refereed by John McCarthy, former UFC referee and Gracie's trainee, or he would not fight. Despite the legend status of Gracie, the yokozuna had trained now under famed personal trainer Maz Tanaka and would be Royce's biggest opponent, so it was believed he could overcome Royce's Brazilian jiu-jitsu groundwork by smothering him with his large size advantage. Come the match, Akebono charged towards Gracie and pushed him to the ground, where he passed his guard momentarily before the Brazilian escaped to his feet. Gracie then seized Akebono's arm and locked an omoplata/wrist-lock combination, which the yokozuna was forced to submit to. He stated to be disappointed with his own performance, citing "I did everything my trainers told me not to do."