Andre Berto -- GGG Would Punish Canelo ... And I Want The Winner (VIDEO)

Andre Berto is totally down to take on the winner of a fight that doesn't exist yet ... saying he'd gladly take on the victor in the Canelo Alvarez/GGG mega-fight ... if it ever happens.

We got Berto out in Beverly Hills and asked him about the fight ... which is the second biggest dream fight out there (Mayweather/McGregor #1) and who he thinks would take it.

Berto -- a former world champ says he thinks GGG would be too much for Canelo but who ever wins ... HE WANTS TO FIGHT THAT GUY.

Glad to hear somebody wanting to fight somebody ... c'mon guys make this happen.