Gabriel Santisima delivered a career-best display to upset Subaru Murata (10-1, 10 KOs) with a 10-round decision win in an absorbing battle of southpaws from Japan's Korakuen Hall for a regional 122-pound title.

96-93, 96-93 and 97-92 were the scorecards favoring the 21-year-old (10-1-1, 7 KOs), whose relentless pressure and counterpunching worked a treat against a highly-regarded foe many expected to finish him in the later rounds.

Murata, ranked No. 7 by the WBC and WBA, couldn't mask his surprise nor claw back any semblance of control after being floored midway through a pulsating fight where he danced with danger and paid the price.

Showcasing his fast hands in round two, the 29-year-old was forced to think about his advances against a younger, bullish underdog charging forward early and often.

Murata, rated No. 9 by The Ring among junior featherweight contenders for Naoya Inoue's crown, ended a nine-month layoff with this outing and the heavy favorite adopted a measured approach as a more active visitor kept him honest, working well behind the jab and not hesitating to land in-between thrown punches.

That tactic worked well, even as he was being tagged to head and body, as the Filipino caught Murata clean with two sharp right-hands two minutes into the fourth.

Absorbing one to land two or three was Murata's modus operandi in the fifth and while dominant for large parts of the sixth, it backfired spectacularly on him in the final moments.

Floored by a counter left hook just before the round's end, that stunning sequence sparked the underdog to double down. He connected big with wide hooks in the seventh, held his feet and traded in round eight before Murata replied by winning the final two frames based on pressure and punch connects alone. It wasn't enough.

In the card's chief support bout, Shori Umezu and Fumiya Fuse couldn't be separated over 10 rounds as they fought to an exciting split draw (96-94, 94-96, 95-95), seeing Umezu retain his domestic bantamweight belt.