Kostya flattens him within four rounds at most. Edwin`s chin will get cracked but good once Tszyu lands that right hand on it, and Edwin just couldn`t seem to recover at all from a big shot that put him on ***** street. Kostya was also a very strong guy and he would manhandle Rosario inside, this fight really wouldn`t be all that competitive I feel.
Well if we are talking about when Rosario was actually a champ at jnr welter late in his career when he beat I think Garza for the title, then Tszyu and pretty clearly. But if we talking prime for prime, with Rosario moving up to face him. Much closer call, Kostya's size would take a bit of Chapo's power out of the equation. Would be a shoot out at range which suits both but I just cant see Rosario overcoming the size and power of Tszyu. Chapo was only hammered by big punchers in his prime but if Kostya was anything it was one of those.