Despite the one-sided affair inside the boxing ring Saturday night ... Shawn Porter tells TMZ Sports he truly believes Errol Spence can bounce back and beat Terence Crawford in a rematch down the line.
Of course, after what went down at T-Mobile Arena in Las Vegas, many people have a different opinion ... considering Bud completely picked apart the previously unbeaten fighter for most of the nine rounds that the two went at it.
Crawford landed 185 punches and knocked down Spence three times.