Errol Spence and Terence Crawford have a lot more than their undefeated records and four shiny belts on the line in Vegas Saturday night ... both superstars agree, the winner is the best boxer of this generation!
TMZ Sports is on the ground in Sin City ... and we talked to both fighters just days before the biggest clash of their professional lives.
"I can't wait to show everybody why I am not the best 147-pounder in the world, but the best fighter, period," 33-year-old Spence said.