I agree that if any welter can do it, Williams can. But Floyd is the master at adjusting to an opponent and Williams is flawed enough for PBF to see a way in. Williams has those long arms but likes to fight the small game. PBF could fight even smaller, fighting in so close that Williams' reach is negated and his punch output is severely reduced. Williams' version of defense is offense and if you can take his offense away you can hit him pretty much anytime you want. I say he would do largely what he did to Corrales to beat him. Jab him to the stomach and chest from the outside and then get in.