Japanese boxer Naoya Inoue knocked out Filipino opponent Marlon Tapales in the 10th round Tuesday to become the undisputed super bantamweight champion of the world and just the second man to unify all four major belts in two different weight classes.

The fighter nicknamed "Monster" put on another dominant performance at Tokyo's Ariake Arena as he added Tapales' World Boxing Association and International Boxing Federation crowns to the World Boxing Council and World Boxing Organization titles he already held.

Inoue fought on the front foot from the outset of the bout and scored the first knockdown late in the fourth, getting Tapales on the ropes before he was saved by the bell at the end of the round.

Japanese boxer Naoya Inoue (R) throws a punch at Marlon Tapales of the Philippines during the fifth round of their four-belt world super bantamweight title unification match at Ariake Arena in Tokyo on Dec. 26, 2023. (Kyodo) ==Kyodo

Tapales doggedly fought his way back into the contest, but with Inoue's powerful blows taking their toll and the Filipino battling from behind on the scorecards, the 30-year-old Japanese star landed a savage right that left his opponent unable to recover his feet just over a minute into the 10th.

"It's thanks to the support from all of you I could collect these four belts, a year on from the last one in a different division," Inoue said. "I think super bantamweight is the right division for me at the moment and I'll strive to show a stronger version of myself next year and the one after."

Inoue praised his 31-year-old opponent for putting on a tough battle at the same venue where the Japanese power puncher made his super bantam debut in July, dethroning WBC and WBO incumbent Stephen Fulton in an eighth-round stoppage.

"(Tapales) was an extremely tough and mentally strong boxer, as I expected before the match. I'm relieved to have beaten such a boxer after 10 rounds and proved what I've been doing was right," Inoue said.

Japanese boxer Naoya Inoue (R) reacts after knocking down Marlon Tapales of the Philippines in the 10th round their four-belt world super bantamweight title unification match at Ariake Arena in Tokyo on Dec. 26, 2023. (Kyodo)

The Kanagawa Prefecture native moved up in weight after unifying all four bantamweight belts last December and has indicated he plans to move up again down the road.

He was strongly favored by bookmakers over Tapales, who earned his world titles in a controversial split-decision win against Uzbekistan's Murodjon Akhmadaliev in April.

Despite being confident that he was ahead on the cards, Inoue said he remained wary of his opponent's potential to throw a knockout blow and had not expected the fight to end when he landed a straight right through Tapales' guard in the 10th.

Japanese boxer Naoya Inoue poses after defeating Marlon Tapales of the Philippines in their four-belt world super bantamweight title unification match at Ariake Arena in Tokyo on Dec. 26, 2023. (Kyodo) ==Kyodo

"Honestly, I was surprised to see him drop in the 10th round. But I had accumulated good punches, so I believe he had taken quite a bit of damage," Inoue said. "I could tell while fighting he had one big punch in him and I'm sure my corner was feeling that too."

American Terence Crawford in July became the first boxer to unify the four championships in two weight classes when he conquered the welterweight division, adding to his undisputed super lightweight title from 2017.

The undefeated Inoue, who has won world titles at four different weights and became the first Japanese to top the pound-for-pound rankings published by the prestigious Ring magazine in June 2022, improved to 26 wins with 23 knockouts. Tapales dropped to 37-4.

The Filipino fighter said he had no illusions about the quality of his opponent but had still been "surprised" by his speed.

"He was extremely fast, and not managing to catch up was the deciding factor in my defeat," Tapales said.

Asked his advice for Inoue's next opponent, Tapales simply offered, "Good luck."

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