Japanese boxer Junto Nakatani became a three-division world champion Saturday by claiming the WBC bantamweight crown with a sixth-round stoppage of Mexico's Alexandro Santiago.

The undefeated 26-year-old southpaw was one of three victorious Japanese fighters in a world title tripleheader at Tokyo's Ryogoku Kokugikan, with Takuma Inoue defending his WBA bantamweight belt and Kosei Tanaka crowned WBO super flyweight champion.

Japanese boxer Junto Nakatani poses with the WBC bantamweight championship belt after winning the title against Mexico's Alexandro Santiago at Tokyo's Ryogoku Kokugikan on Feb. 24, 2024. (Kyodo)

Nakatani previously held the WBO world flyweight and super flyweight belts before making his bantamweight debut against Santiago.

The 28-year-old Santiago was making his first title defense since winning the vacant WBC championship in a unanimous decision against Filipino great Nonito Donaire last July.

Nakatani looked well ahead on the cards when he scored the first knockdown of the fight with a straight left less than a minute into the sixth.

With Santiago still reeling, Nakatani delivered a combination culminating in a right hook that put his opponent back on the canvas and prompted referee Laurence Cole to stop the fight one minute and 12 seconds into the round.

"Coming up to this fight, I spent many hours training in Los Angeles and Japan. I just want to thank Alexandro for tonight," said Nakatani, who improved to 27 wins with 20 knockouts.

"Getting the WBC bantamweight belt is such an honor, especially as so many Japanese boxers have held it before me."

Santiago dropped to 28-4 with 14 wins by knockout and five draws.

Japanese boxer Junto Nakatani (L) battles Mexico's Alexandro Santiago in a WBC bantamweight world title fight at Tokyo's Ryogoku Kokugikan on Feb. 24, 2024. (Kyodo)

Takuma Inoue, the younger brother of undisputed super bantamweight king Naoya "The Monster" Inoue, completed the first defense of his title with a ninth-round body shot knockout of Filipino former champion Jerwin Ancajas.

With his superstar brother in his corner, the 28-year-old Inoue (19-1, 5 KOs) had absorbed several heavy shots before hitting his opponent with successive rights to the midsection early in the ninth. The second punch floored Ancajas (34-4-2, 23 KOs), handing him his first defeat inside the distance.

"Coming into tonight, I knew my opponent would be the best I had faced," the WBA bantamweight champ said. "(Ancajas) was so skilled and so strong. Winning against him has really given me confidence."

Tanaka (20-1, 11 KOs) earlier won the vacant WBO super flyweight crown by unanimous decision against Mexico's Christian Bacasegua (22-5, 9 KOs). The 28-year-old Tanaka became the third Japanese man to win belts in four divisions, following Kazuto Ioka and Naoya Inoue.

Japanese boxer Takuma Inoue (C) is flanked by brother Naoya (L) and father Shingo after defending the WBA bantamweight belt against Jerwin Ancajas of the Philippines at Tokyo's Ryogoku Kokugikan on Feb. 24, 2024. (Kyodo)

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