Gabriel upset previously-unbeaten contender Subaru Murata on February 7, outhustling the Japanese talent to earn a gritty 10-round decision at Tokyo's Korakuen Hall.

That victory helped give Alex, one of six brothers who box, the confidence needed to stop Yukinori Oguni 1:08 into the eighth round of their 10-round contest at the famed venue on Sunday.

Oguni (24-5-3, 9 KOs) had been riding high after upsetting former unified junior featherweight champion Marlon Tapales on April 3, but Santisima gained some revenge for his compatriot.

At the time of the stoppage, the Filipino was slightly ahead on 67-66 on two scorecards, while the other had Oguni up 68-65.

"I really worked hard during training camp to get the victory and prepared for this," Santisima (14-2, 8 KOs) told The Ring.

"I hit with him a lot of clear, solid punches and the referee saw that it was enough [to stop the fight]. I knew it was a big opportunity and gave it my all. I want to thank my promoter Jim Claude Manangquil, manager Nobuyuki Matsuura and trainer Michael Domingo, who got me this kind of fight."

Santisima remained calm about gatecrashing the division and seizing Oguni's No. 10 spot in The Ring ratings.

Similarly, he isn't throwing names around and prefers to let his team take care of his career.

"I will continue to train harder and develop, to be ready for harder fights next," he said.

Naturally, the 26-year-old's promoter Manangquil was in a buoyant mood.

"It was good he got revenge for his stablemate," he said. "It was a great performance; he really stepped up. We're gonna see what Alex's best possible fight is now, Oguni wants a rematch too, we're in no rush but will see."