Boxer Victor Ortiz: Modeling Man Panties Before Mayweather Fight

Floyd Mayweather's next opponent is the total package ... in more ways than one ... and last week, he let it all hang out in a SUPER-REVEALING underwear photo shoot ... and TMZ has the pics.

WBC World Welterweight Champion Victor Ortiz is now the spokesman for an underwear site called Freshpair.com -- and as part of the deal, the 24-year-old agreed to model some of his favorite undies.

Mayweather is a HUGE favorite in the Sept. 17 fight -- but Ortiz is clearly the knockout.