Kostya had focus ,timing and big pucussive power from it all put together.
Pac and Mayweather have a sharper faster accumulation style damage that Ricky will find harder to cope with in the later rounds.If he does damage fast in the first 5 rounds he has a hope but I think its a repeat of Floyds style of fight against him and he wont have the patience after all else fails early on.

Kostya fought Rickys fight and even said he would fight his fight from the start so the younger fitter more hungary man deservedly won, these other two mentioned dont fight like that he will find it hard to catch Pac clean once he goes off plan. Im with Pac so long as he doesnt get dragged into a phone box style fight which I dont think he will, so long as hes got the legs he'll use them.