Knocking the more younger,stronger and undefeated boxer like Thurman in the first quarter of the bout is really devastating in their part since they are well prepared on this fight
It will still be Pacquiao for sure. Thurman owns a few rounds, I think that is rounds 5-9 or 5-8. Without the knockout, that would be Thurman's round so let's say he won the first round but 2nd and the following rounds favors Pacquiao. And then there is the liver punch. If there will be no knockdown in round 1, there would still be one in the next rounds since if Thurman would never be aware of that punch, he will never change his tactic.
I'm sure Thurman's team was aiming to get ready for the rematch of Pacman ASAP. I can see it on his eyes that he fail the way he talks about it on their last interview.