World Boxing Council super-flyweight champion Masamori Tokuyama stopped 12th-ranked challenger challenger Eric Lopez by technical knockout Monday when the Mexican could not answer the bell for the seventh round.
Referee Frank Cappuccino of the United States stopped the fight following the sixth round after Lopez' right eye had swollen shut after being rocked by a left uppercut in the third round at Saitama Super Arena.
Tokuyama, a pro-Pyongyang Korean resident of Japan, dominated the 12th-ranked challenger throughout the scheduled 12-rounder, throwing left-right combinations while also scoring with hard left uppercuts to claim his fifth successful title defense.
"I don't think I fought very well. I was lacking power in my knees and was unable to move forward. This was probably due to my weight loss," said Tokuyama, whose Korean name is Hong Chang Su.
"I was able to connect with my left a lot and I'm happy with the victory," he added.
The win brought Tokuyama's record to 27 wins, including eight by knockout, two losses and one tie. Lopez fell to 17-12-3.
Tokuyama and World Boxing Association (WBA) super bantamweight champion Osamu Sato are currently the only two reigning world title holders who train at gyms in Japan.