That would be a big win by him if he can make it, Spence needs to KO Pacquiao if he wants to win in the decision, in terms of technique, Manny should win by the judges score that's why it's important Spence should be the one who is the aggressor.
This is a huge win for Spence if he can Knock off Pacquaio since imagine he take down the legendary for sure his rank and popularity will increase after this.
True, because most fans do not consider the KO loss of Manny against Marquez was a good one, they will always think Marquez just got lucky. If Spence will KO Pacman, I guess that would send Manny to retirement, a thing that Thurman promise but failed to do to him.