When Tongan-Australian MMA fighter Isi Fitikefu steps away from the thunder of punch combinations and grappling drills, his competitive fire does not cool. He simply switches the playing arena, from rings to courts. Instead of boxing, the 33-year-old can be found chasing dinks and match points on a pickleball court, attacking the paddle sport with the same intensity he brings to the cage. As Fitikefu prepares to face undefeated American newcomer Chase Mann on Friday, January 23, at ONE Fight Night 39: Rambolek vs Dayakaev on Prime Video, pickleball has become far more than a casual hobby.