Mike Tyson Says Errol Spence, Terence Crawford Fight Will End In Knockout

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."