Japan’s Naoya Inoue knocked out Marlon Tapales in the 10th round in Tokyo to become a two-weight undisputed champion.
Inoue, 30, put in a ruthless performance to add Tapales’ IBF and WBA super-bantamweight belts to his WBO and WBC titles.
Inoue became undisputed bantamweight world champion last year but vacated the belts to move up a division.
“I think super-bantamweight is my weight division for now,” he said.
“Next year and the year after that, I want to prove that I can become an even stronger fighter.”
Inoue is only the second male boxer to unify all four world titles in two different weight classes after American Terence Crawford.
He made his debut at super-bantamweight in the summer when he sensationally stopped American Stephen Fulton to claim the WBC and WBO belts.
However, he had to dig deep against 31-year-old Tapales, dropping the Filipino in the fourth round, before landing a hard right hand in the 10th to claim his 26th career victory and 23rd by knockout.
Tapales upset Murodjon Akhmadaliev of Uzbekistan by split decision to win the IBF and WBA titles in April.
“He was very tough with a strong mentality,” said Inoue, who has also won world titles at light-flyweight and super-flyweight.
“I think the way I was able to knock out a strong fighter like that in the 10th round is proof of all I’ve been doing, so I’m relieved.”
Following the bout at the Ariake Arena, Inoue, nicknamed ‘The Monster’, hinted at a big fight in the spring of 2024.
“I think a lot of people know the rumour of a fight coming about in May,” he said. “But I can’t say much about this yet because we’re under negotiation.
“But I want to make everybody happy so that I can show you a great fight next year as well.”