Ye Joon Kim asked for it and Naoya Inoue was more than happy to deliver.

A classic one-two by The Ring and undisputed junior featherweight king floored South Korea's Kim to end their championship affair. Referee Mark Nelson immediately halted their contest at 2:25 into the fourth round of their Lemino Pay-Per-View/ESPN+ main event Friday evening from a sold-out Ariake Arena in Tokyo, Japan.

Yokohama's Inoue (29-0, 26 KOs) fought at a measured pace in the opening round as he sized up his late-scheduled opponent. Kim (21-3-2, 13 KOs) received his first title opportunity as an emergency replacement for inured IBF/WBO mandatory challenger Sam Goodman (19-0, 8 KOs) on just eleven days' notice and did his best to catch Inoue off guard.

"I didn't have a lot of time to study my opponent," Inoue said, as translated by Mizuka Koike.

That plan included Kim fighting out of the southpaw stance—a habitual practice by the switch hitter—and waited for The Ring's No. 2 pound-for-pound fighter to make a mistake or even take an unnecessary risk.

It was never going to happen, though it didn't prevent Kim from at least having his moment.

Inoue—a four-division champion and The Ring's 2023 Fighter of the Year—kicked into high gear in the second. He mixed in a straight right hand between a series of left hooks. Kim smiled and nodded every time he tasted Inoue's power, though the developing mouse under his left eye indicated the damage he absorbed throughout the brief affair.

Kim connected with combinations in an entertaining third round. Inoue took all the shots well and constantly adjusted every time his opponent enjoyed any modicum of success.

Inoue continued to chip away at Kim's confidence in the fateful fourth. Kim put on his best poker face as Inoue landed to the body, and again when he connected with right hands and left hooks to the chin.

Kim's response on almost every occasion was either to nod, wave in Inoue or even both.

Inoue gladly accommodated that request in the final moments of fight. A series of power shots drove Kim into a corner before Inoue closed the show with a jab and a right hand. The latter sent Kim to the canvas for the bout's lone knockdown, at which point the fight was stopped.

The early win was the tenth straight knockout registered by Inoue, including all five fights at junior featherweight since he moved up from bantamweight in 2023.

Inoue successfully defended The Ring 122-pound championship for the third time and made his fourth overall defense of at least two junior featherweight belts. Inoue is now a perfect 21-0 in fights with a primary version of a sanctioning body title at stake.

His current reign at the weight began with a July 2023 eighth-round knockout of then-unbeaten WBC/WBO titlist Stephen Fulton. Inoue then claimed The Ring championship and the WBA/IBF belts after a Dec. 2023 tenth-round knockout of Marlon Tapales to become a two-division undisputed champion.

Friday also saw Inoue fight in his home country for the eighth straight time. The run dates back to 2021 after a pair of appearances in the U.S., where he is now prepared to return later this spring.

"it was another great performance by our champion here," said Hall of Fame promoter Bob Arum, whose Top Rank company co-promotes Inoue with Ohashi Promotions. "I observed the great company of Japan has given [Major League baseball great Shohei] Ohtani to the city of Los Angeles.

"For his next fight, the great country of Japan will give us the great Inoue to the city of Las Vegas for one fight this spring."

Inoue seconded that notion, confirming his plan for a three-fight 2025 campaign as he previously shared with The Ring.

"2025 will be the year for me to go to other countries to fight," Inoue reiterated. "Next, I will be going to the city of Las Vegas to show you a great fight.

"I am planning to fight in Las Vegas and then Saudi Arabia later this year. Please support me in my journey around the world."

Jake Donovan is part of the U.S. team for The Ring. Follow Jake on X and Instagram.