Andrew Berto says Tenshin Nasukawa has a huge chance ... the chance to ruin Floyd Mayweather's legacy FOREVER, all he's gotta do is go in there and beat Floyd.
Mayweather is 50-0 and has beaten everyone from Canelo Alvarez to Oscar De La Hoya ... but, according to Berto, that all goes out the window if he loses his December 31 exhibition match with Tenshin.
"It would tarnish it for sure. You cant be 50-0 fighting some of the best fighters in the world then get knocked out by some kid."
Berto faced off against Mayweather back in 2015, and says the chances that Tenshin gets the upset in Tokyo are SLIM ... but sees one strategy he can use to pull off the upset.
"Go in there and try to knock his head off, and if you throw a kick ... f**k it."
It's going down in a couple days, 3 3-minute rounds for an eight figure payday, a lot of fun, and maybe Floyd's reputation ... could it happen?
Stranger things have.