Japan's unbeaten "Monster" Naoya Inoue defended his WBA and IBF bantamweight titles on Tuesday with an eighth-round technical knockout win over unheralded Thai challenger Aran Dipaen in Tokyo.
Fighting at Ryogoku Kokugikan –- the home of sumo –- Inoue wore Dipaen down with a series of punishing shots before dispatching him with a vicious left hand.
The bout, Inoue's first in Japan for around two years, was widely seen as a stepping-stone towards an attempt at unifying all four bantamweight belts next year.
But the 28-year-old was made to work hard for his win over Dipaen, who absorbed a series of heavy body blows with little visible impact.
"He used to be a Muay Thai fighter and he brought that toughness," Inoue said of Dipaen, who went into the fight with a 12-2 record.
"I started to wonder whether my punches were having an effect -- that's how tough he was."
Inoue took his unbeaten record to 22-0, with 19 wins by knockout.
After hammering away on Dipaen's body, Inoue finally put the challenger away with a big left that sent him down to the canvas.
"The fight didn't go as everyone was expecting, but it was good to fight in Japan again after two years," Inoue said.
Inoue has set his sights on unifying the bantamweight belts next year, with WBA champion Nonito Donaire and WBO title-holder John Riel Casimero standing in his way.
But he warned that he could turn his attentions elsewhere if no agreement could be reached with either fighter next year.
"I've been placing a lot of importance on unifying the four belts, but if the individual fights don't happen, I'll start thinking about the super-bantamweight title," Inoue said.
Inoue beat Donaire in the final of the World Boxing Super Series in 2019, claiming a unanimous points win over the veteran Filipino after an epic contest.
But Donaire went on to win the WBC belt earlier this year, and defended it in style at the age of 39 against countryman Reymart Gaballo on Saturday.
Casimero, meanwhile, pulled out of his WBO title fight against Britain's Paul Butler in Dubai on Saturday after missing the weigh-in.
Reports said the Filipino was admitted to hospital with viral gastritis, and the WBO has ordered him to present his medical documents before December 20 or face being stripped of his title.