Nasukawa's father threw in the towel after 140 seconds of the first round as his 20-year-old son bravely teetered around the ring trying to get up.
It was a quick and definitive victory for the 41-year-old American. Mayweather was gracious in victory, hugging the weeping Nasukawa and calling him "still a great champion." Nasukawa, however, barely landed a clean punch against the vastly more experienced Mayweather.