Normally when Floyd is pitted against ATG WWs, he is at a natural size disadvantage (i.e. against Hearns or Robinson). Not here. Sure, Floyd was a junior lightweight at the start of his career but Napoles started as a featherweight and spent most of his 20s between lightweight and light welterweight so was always a small WW. Their physical stats are very similar - height and reach are practically identical. You've got to figure Napoles has the advantage in power but he could also put his punches together better than Floyd, who wasn't a great combination puncher. Speed, the edge is to Floyd...but Napoles was super slick defensively as well. I think Napoles wins this because he was naturally more aggressive and puts his punches together better and had the slickness to offset Floyd's defense. He'd outwork Mayweather and take a competitive but clear decision. Good matchup though.