Reito Tsutsumi weathered early pressure from Leobardo Quintana to triumph but Taiga Imanaga fell short in a split-decision to Eridson Garcia at The Ring V: Night of the Samurai.
The former, contesting just his fourth professional bout, sought to keep his ambitions for a world title inside his first ten fights on track with a fourth-round technical knockout win.
But his countryman was edged by his opponent, suffering an eighth-round knockdown on his way to a 96-93, 95-94 and 94-95 loss in what was the first defeat of his career.
The Japanese pair formed part of a stacked slate featuring several Far East stars at Riyadh's Mohammed Abdo Arena, capping off a busy 2025 for boxing in Saudi Arabia.
Fighting on the undercard of Naoya Inoue's undisputed super-bantamweight title defence against Alan Picasso, Tsutsumi was seeking to emulate unbeaten brother Hayato.
He did so against Quintana, who forced him under significant pressure in the early exchanges, leaving the super-featherweight star with a bloodied face off the front foot.
Tsutsumi however exploded halfway through the eight-round cotnest and staggered his foe with a ruthless left hook, before crashing two rights to send him down to the canvas.
Imanaga meanwhile looked to be on the front foot, albeit narrowly, against Garcia in their lightweight contest, and sought to exploit his opponent's pace around the edges.
Yet he wobbled late in the seventh, and found himself dropped to the canvas in the eighth, a blow from which he never really recovered as he fell short in the championship rounds.
Defeat likely means a return to the domestic division as he looks to rebuild, but will only further burnish Garcia's stock as he looks to push on into a busy 2026.
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