Hulk only knocked out Juggy once cuz it was a psionic backlash, which is pretty much the same thing as mindwiping, and Hulk didnt even realize wut happenned cuz the psionic backlash was not of his doing, it just came from his mind. That's the only way to ever knock out Juggernaut, by attacking his mind. Otherwise ur shit outa luck cuz u cant physically knock out Juggernaut, i bet not even Big G could.