Mayweather also ensured that the rules were changed because despite Rizin having it in the contract that both men would fight with their brand's gloves, Mayweather took to the ring with his usual Grand brand.
Showtime Pay-Per-View will air their 12-round, 147-pound title bout as the main event of a four-fight broadcast from MGM Grand Garden Arena.
Floyd Mayweather was paid $9 million to beat up a non-boxer who is significantly smaller than him.
Floyd Mayweather made short work of Nasukawa in this exhibition bout. Mayweather toyed with him throughout.
The fight, which was held in Saitama, Japan, was scheduled to last for three rounds but Mayweather quickly swept aside his opponent. Mayweather, who first retired in September 2015, stopped Ireland's McGregor in the 10th round in August 2017, and Muhammad Ali fought Japanese wrestler Antonio Inoki in a 15-round draw in 1976. They wanted this to happen over here in Japan, so I said why not.
It was an unexpected turn of events, and the rule set was even more freaky. We had fun. Tokyo, you were fantastic, but I'm still retired. I am still retired, I don't look to come back to boxing.
The opening round starts off with Nasukawa circling towards the left jab of Mayweather, who had a big smile on his face and was slowly walking Nasukawa down.
And another half-hearted punch to the side of the head did in the kickboxer a third time - and his corner threw in the towel after 136 seconds of the fight. Mayweather landed a good body shot and a left hook and Nasukawa goes to the mat. He's still a true champion. "Tenshin is still a champion and a great fighter". He's a great guy, he's a guy fighter. I want the fans all around the world to support Tenshin.