Junto Nakatani made a successful first defense of his WBO super flyweight title Monday with a unanimous decision over Mexico's Argi Cortes.
Nakatani knocked Cortes down twice in the fifth round and again in the ninth en route to improving his record to 26-0 with 19 knockouts.
The 25-year-old left-hander got smacked by a right from the challenger in the sixth round but managed to stay on his feet at Tokyo's Ariake Arena.
Two judges scored the bout 119-106, while the other scored it 118-107.
"I wanted to show a convincing victory," Nakatani said. "I scored a knockout in the final round of my previous bout, so I tried to do the same but I just couldn't because of Cortes' mental strength. This is a good experience."
Cortes fell to 25-4 with 10 KOs and two draws.
In the day's other world title match, WBA and WBC light flyweight champion Kenshiro Teraji of Japan successfully defended his titles with a ninth-round technical knockout of South Africa's Hekkie Budler.
In a non-title eight-rounder, former kickboxer Tenshin Nasukawa defeated Luis Guzman Torres by unanimous decision in his second match since becoming a pro boxer.