It's difficult to definitively say who would win in a fight between Juggernaut and Superman as it largely depends on the specific circumstances of the battle. Juggernaut is incredibly strong and virtually indestructible when in motion, thanks to his mystical powers. Meanwhile, Superman possesses a wide range of superhuman abilities and powers, making him one of the strongest beings in the DC Universe. Ultimately, the outcome of such a battle would be subjective and open to interpretation.