Japan's unbeaten Naoya Inoue said he was mentally "exhausted" after knocking out a goading Ye-joon to retain his undisputed world super-bantamweight titles in Tokyo on Friday.
Inoue is expected to take his prodigious skills to Las Vegas for his next fight and he bid farewell to his adoring fans in the Japanese capital with another ferocious performance.
The 31-year-old "Monster" landed a juddering one-two combination near the end of the fourth round to knock out the South Korean, who stepped in to replace injured Australian Sam Goodman just two weeks before the fight.
𝗧𝗛𝗘 𝗠𝗢𝗡𝗦𝗧𝗘𝗥 𝗜𝗡 𝗦𝗟𝗢𝗪 𝗠𝗢𝗧𝗜𝗢𝗡😲
— BoxingScene.com (@boxingscene) January 24, 2025
Check out the huge right hand from Naoya Inoue that BLASTED Ye Joon Kim out in Round 4💥
📽️ @trboxing pic.twitter.com/cC1NfsnwYe
The bout had already been postponed by a month from its original 24 December date when Goodman suffered a cut above his eye in training.
Inoue said the disruptions had taken a toll and described the win as "a weight off my shoulders".
"I'm exhausted, but more than being physically tired, there has been a lot going on in the past two months," he said.
"My opponent got injured and the fight was postponed, then I got a different opponent. It has been difficult mentally."
The Naoya Inoue era.
— Top Rank Boxing (@trboxing) January 24, 2025
👑👑👑👑 pic.twitter.com/YzNTIZ5xkb
Inoue, who took his record to 29-0 with 26 knockouts, said his plan was to fight in Las Vegas in the spring.
He has also been tipped to fight in Saudi Arabia later this year after signing a sponsorship deal with the country's Riyadh Season.
He has not fought outside Japan since he beat Michael Dasmarinas in Las Vegas in June 2021.
"I don't know how complete I am as a boxer. I want to keep training so that I can keep improving until the end of my career," said Inoue.
THUNDERING COMBINATION
The 32-year-old Kim, who grew up in an orphanage and did not take up boxing until he was 20, is ranked No 11 by the WBO in the super-bantamweight division.
He had the chance to become South Korea's first male world champion in almost 20 years but he had no answer when Inoue turned up the heat in the fourth round.
Kim's fate was sealed when he reacted to an attack from Inoue by gesturing for the champion to come at him again.
Inoue duly obliged, landing a thundering combination to send the Korean to the canvas.
Naoya Inoue knocks out Ye Joon Kim in the 4th round to retain the undisputed super bantamweight title. pic.twitter.com/MaLzvwBSNu
— b0xingfan (@b0xingfan) January 24, 2025
"I was planning to knock him out anyway so I don't think he really needed to do that," Inoue said.
Kim had beaten all seven Japanese fighters he had faced previously but said Inoue was "faster and stronger than I thought he would be".
"Of course I came here to win, so this is difficult for me to take," said Kim, who was fighting for a world title for the first time.
"My tactics were to get Inoue to come close to me and then hit him on the counter."
It was Inoue's third title defence since becoming undisputed super-bantamweight world champion in December 2023.
It was also his 10th straight knock-out win.
Inoue said he was glad the fight was finally over.
"I gave everything to be ready for the fight in December, and then it was postponed 10 days before it was supposed to happen," he said.
"Then I gave it everything in training for the month after. I didn't really feel it when I was training hard, but now that the fight is over, I feel very tired."