Oguni, who is now The Ring's No. 10 junior featherweight, will look to continue that momentum against Alex Santisima Jr. on August 16 in their scheduled 10-round contest at Korakuen Hall, Tokyo.

"I want to win this upcoming bout convincingly and build on that for the next one," Oguni (24-4-3, 9 KOs) told The Ring.

"I see this as a crucial fight that will determine whether I get a world title shot or have to retire."

Heading into his previous bout with Tapales, the Japanese warrior looked a shadow of his former self and was widely expected to lose to the Filipino, who entered as The Ring's top-rated player at 122 pounds.

The 38-year-old is closing in on a decade since briefly reigning as IBF champion.

Tapales was a southpaw and Oguni had suffered losses to southpaws in three of his four defeats, as well as enduring mixed form with just two victories from his last six before their meeting. Regardless, he was aware of a do-or-die moment and found a way to score one of the year's biggest upsets so far.

"My mindset was, 'If I lose, I'll retire, if I win, I might be able to make a comeback on the world stage," he said.

"I held off on throwing body shots early on. Since throwing them in the early rounds would make him weary, I held off until the fourth round, waiting for the moment when he let his guard down and came at me.

"I'd never beaten a southpaw before, so was nervous but winning this fight has given me the confidence that I can handle even the world’s top southpaws."

Afterwards, Oguni accepted he celebrated his big moment a little too much.

"I had a lot to drink with some people who'd been cheering me on," he said. "When I sat down on the train home, I couldn't stay awake and fell asleep. I missed my stop and ended up travelling much further than I meant to, that's how plastered I was."

Looking towards the future, Oguni would like to test himself against Ring and undisputed 122-pound champion Naoya Inoue. Aware it's an unlikely option, the 38-year-old will keep pushing forward with other targets instead.

"I want to win a world title," he said. "I'd like to fight Ramon Cardenas. In Japan, Cardenas is famous for fighting Inoue and I'm confident, I think I can beat him."

Cardenas (27-2, 15 KOs) scored a fifth-round knockout of Erik Robles in December 2025, ending an eventful year with a highlight reel finish after falling agonisingly short against Inoue seven months earlier. The 30-year-old is slated to return later this month in a 10-rounder, facing Colombia's Leonardo Carrillo (20-1-1, 9 KOs) on August 29.

Santisima Jr. (13-2, 7 KOs), a five-year professional, won his first eight appearances before suffering a seventh-round knockout by highly-rated hopeful Subaru Murata (10-1, 10 KOs ) in 2024, who also beat Oguni. After rebuilding at home, he was stopped in five rounds by Wensong Liu (TKO 5) in June 2025 but has won two straight.