1976-04-03 Rigoberto Riasco w rtd 8 (15) Waruinge Nakayama, New City Gym, Panama City, Panama - WBC
1976-04-03 Rigoberto Riasco w rtd 8 (15) Waruinge Nakayama, New City Gym, Panama City, Panama - WBC. Referee: Carlos Berrocal. With his superior firepower, Riasco (121¾) took the fight to Nakayama (121¼), dropping his rival with right hands in the fourth and seventh rounds, and despite being cut over the left eye in the seventh he was landing at ease in the eighth to force a retirement at the end of the session. It was a shame, but having been ultimately outpunched after making a bright start, Nakayama’s right eye was closed and his other eye was shutting fast, thus leaving his corner no other option than retiring him. By his victory, Riasco would become the first champion of the new weight class.