Mike Tyson might not know who will win the Errol Spence vs. Terence Crawford fight, but he is sure of one thing ... it's definitely ending in a knockout.
TMZ Sports got Iron Mike's prediction on the massive match just before the two star boxers officially square off Saturday night at T-Mobile Arena in Las Vegas ... and he seemed to kind of like Bud to win it.
Then again, he wasn't super confident about it all ... telling us a recent talk he had with Spence was changing his mind a bit.
He did, however, have one guarantee about the tilt ... and that's that it ain't going all 12 rounds.
"After seeing them both fight, I know it's not going to last," the boxing legend said. "I think it's going to end in a knockout."
Fight night kicks off at 8PM ET/5PM PT on Showtime PPV ... and now that you're armed with some knowledge about it from one of the sport's GOATs -- getcha betting slips in now!!