I, personally, can't stand the Juggernaut. He's kind of annoying, to be quite honest.
However, he can't be hurt by physical means. Any physical means.
The Hulk Killer Humanoid only HAS physical means to hurt him. The means that, no matter what the Juggernaut can or can't do to the HKH, the HKH has NO HOPE of beating the Juggernaut.
It's like putting Mr. Immortal in a fight to the death. You can't beat him. Even if Mr. Immortal can't do shit to his opponent, he literally CAN'T POSSIBLY lose.
Same thing here - Juggernaut can't POSSIBLY lose.
And, eventually, the HKH would get electrocuted and destroyed. Even just via probability. The fight would, eventually, find it's way to a hydroelectric dam or some such.