The Rizin Fighting Federation organizers are even willing to placate Mayweather by undertaking the weigh-in in his hotel room.

Despite everything, VIP seats are going for 100,000 yen (around $900) each at Saitama Super Arena, on the northern outskirts of Tokyo.

There's little Nasukawa has in common with Mayweather, apart from both being unbeaten. Nasukawa is undefeated as a kickboxer at 27-0 and undefeated in mixed martial arts at 4-0.

He said he never was much of a Mayweather fan, usually cheering for his opponents, such as Manny Pacquiao. And when he met him in person, Nasukawa said he was a little disappointed that Mayweather wasn't as charismatic as he thought he was.

"I sensed no aura about him," he said.

"He says such provocative stuff I feel like kicking him."

Nasukawa said he can't allow the taller and heavier Mayweather to land a single punch in their three rounds. He plans to use his kickboxing nous to avoid getting hit.

"He is the best so I can't let my guard down. I'm sure his punches are fast but I'm sure I can see them.

"I feel excited, although some days I still feel afraid," Nasukawa added. "But when the day comes, I want to fight with confidence."

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