Kazuto Ioka defended his WBA bantamweight crown for the fifth time on Sunday, winning a unanimous decision over Noknoi Sitthiprasert of Thailand.
In the first title fight on the card at Edion Arena Osaka, Shohei Omori lost his first world title fight, suffering an 11th round technical knockout against Marlon Tapales of the Philippines.
Ioka's victory against the second-ranked challenger equaled the Japanese record of 14 world title-fight victories by Yoko Gushiken.
“There were some tough spots,” the 28-year-old Ioka said of his 12-rounder. “I don’t think this record belongs to me but to all the many people, including my fiancee, who have supported me. This is due to them.
"I wanted to finish him with a knockout."
Although he was unable to knock down his Thai opponent, Ioka was able to score repeatedly with his right and was not in real trouble. Early on, Noknoi was able to keep Ioka at bay with his left, but eventually the champion came around. He set up the Thai with jabs to the head and body before delivering his strong right.
Ioka's career record improved to 22-1 with 13 wins by knockout. Noknoi, 30, saw his impressive career total drop to 62-5.
Omori's fight had been scheduled as a title defense for Tapales, but the 25-year-old had failed to make the weight and the crown was vacated when Omori failed to win it.
Omori, 24, was knocked down in the 10th by right hook and was pummeled from the start of the 11th round, when the referee stopped the fight after 16 more seconds. Omori's record fell to 18-2.
The two had fought in December 2015, when Omori also lost by TKO.