I would say Castillo 1 Maidana 1 Cotto Oscar Pacquiao Augustus Chavez Judah Castillo 2 Maidana 2 Hatton honorable mention. I basically ranked it based on how much control he had over the fight. I think his most difficult fights were fights the opponent was threatening to control the distance and thus made Floyd have to either fight them off or be extremely sharp and negative. With Castillo, Maidana, and Cotto, these guys were cutting the ring off and forcing Floyd to exchange on the inside once against the ropes. With Oscar and Pacquiao, their feinting and gradual edging him to the ring and ambushing caused Floyd to have to edge rounds on clean punching and pay extreme attention to detail because one mistake could cost him the round. With Augustus and Chavez, Floyd was never in danger of losing, but they were so relentless he had to work every second. Floyd never seemed to lose control against Judah but he was being outsped and outboxed and out-timed early, which is rare, and he ate some hard punches. Castillo and Maidana 2 were an example of Floyd having to fight as negative as possible to avoid the pressure. I don't think Floyd's lateral movement is inherent to his style contrary to how people describe him, so he has to put in effort to avoid the ropes and still score for 12 rounds. Hatton gets honorable mention because while he made Floyd fight his fight with his footspeed and pressure, Floyd was strong and skilled enough to comfortably outwork him there, so I can't say it as too tough for him. Corley should get an honorable mention too, he had some rough moments in a fight he knew he could win slugging it out. Shane had one of the best single moments but it didn't end up being a tough fight for Floyd.