Mayweather, 41, required barely two minutes to drop the 20-year-old kickboxer three times, before Nasukawa's trainer stepped into the ring and referee Kenny Bayless stopped their bout.
Nasukawa lands a straight left on Mayweather after Mayweather misses a straight right.
"I want to say thanks to god for the turnout, my team, thank you to Mayweather productions and all the entertainment teams,"Mayweather said".
More than anything, though, Pacquiao hopes beating Broner lures Mayweather (50-0, 27 KOs) out of retirement for a rematch later in 2019.More news: Nancy Pelosi fights ‘Trump Shutdown’ with #Resistance luxury vacation in Hawaii
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But don't tell that to Nasukawa, who came out swinging for the fences against the undefeated and retired champion.
"I want to thank God for this turn out and the event".
Nasukawa looked completely out of his depth in his first boxing fight, swinging wildly in an attempt to land a blow on his opponent.
The fight ended in the first round after Nasukawa's corner threw in the towel. "I'm still undefeated. This is just entertainment for the people", he added.
But Mayweather changed his tune after knocking out Nasukawa, who is 27-0 with 21 knockouts in kickboxing and 4-0 with two knockouts in MMA.
But Nasukawa never landed a meaningful punch. Hamasaki, whose record improves to 17-2, has previously fought for Invicta FC, where she was the company's atomweight champion from 2015 to 2016.