Boxer Koki Kameda returned to Japan on Monday and reiterated his intention to retire following his defeat to Kohei Kono on Friday in a WBA superflyweight title match in Chicago.

"Frankly, I'm confident I can still compete," the 28-year-old said at Narita airport. "However, this is my aesthetic: the ultimate is to retire in good form."

Kameda, who was attempting to become the first Japanese fighter to win world championships in four different weight classes, lost by unanimous decision.

"I feel no regrets afterward," Kameda said. "But I wish I could go back in time to before the fight."

Kono, who returned the same day, said his effort in Chicago was better than expected.

"I was really on fire," Kono said. "I was able to fight at a higher level than ever before.

"I always fight with the intent of retiring if I lose, so I really understand that (Kameda's decision to retire)."