Mayweather Jr. could struggle against Canelo

By Reni M. Valenzuela: Despite the emergence of a Gennady Golovkin, what's something special about the famous boxing "duo" which we can't find in other boxers of this generation, so much so that the sport would seem to dim and weaken if they retire? What is in Floyd Mayweather Jr. and Manny Pacquiao that keeps