Superman can defeat Juggernaut, but even he can't stop his momentum once started, because it is a magical ability not a feat of power. So we have an unstoppable object (Juggernaut) colliding with 225 pounds travelling at superluminal speed (Supes).
Superman's power can counter almost all of Juggernaut's abilities. While Juggernaut is very strong and unstoppable, there's very little he can do against a guy who can pack punches with the strenght to move worlds.
The Juggernaut, despite his incredible strength, has been defeated by surprising heroes like Professor Xavier, Cyclops, Banshee, and Lost. These heroes used their unique abilities, whether it be telepathy, strategic thinking, sonic blasts, or reality manipulation, to overcome the seemingly unstoppable villain.
The two brawlers have fought beyond these two encounters, but these two fights establish a few hard facts: the Hulk can be overpowered by the Juggernaut; the Hulk cannot consistently stop the Juggernaut; and most importantly, the Hulk's strength, even at maximum, cannot harm the Juggernaut at his maximum power.
In fact, the two heavyweights have actually squared off before, and the result was far from a tie. In DC Versus Marvel #1, Superman beat the Juggernaut with a single punch.
Fortunately, as long as he has Mjolnir, he won't need to. When the two faced each other in the past, Thor beat Juggernaut by generating an anti-magic whirlwind with his hammer, effectively removing Cain's magical invulnerability.
Juggernaut and the X-Men have had some fierce battles, and while Wolverine has played a key role in beating the Juggernaut — usually using his claws to remove Juggernaut's helmet for the X-Men's telepaths can take him down — he has never defeated Juggernaut on his own.
The Juggernaut is nigh-unstoppable once he gains momentum. Captain America's proto-adamantium shield can stop the Hulk's punch and Mjolnir blows to a dead stop.
After bashing Thor with an entire stone pillar, Juggernaut managed to separate Thor from his hammer – but was unable to lift it as a selfish brute like him was unworthy of its power.
With his near-immeasurable strength, an ability to take even the most devastating blows, multiple attacks that aren't just punching, along with his flight and speed, the Hulk would struggle to keep up with Superman. Even in the few times he's faced Superman, the green monster has lost.
While kryptonite is Superman's greatest weakness, he's susceptible to other forms of energy and threats. This makes Billy Batson — aka Shazam, the World's Mightiest Mortal — one of Superman's greatest opponents. Batson can transform himself into an incredibly powerful adult body when he says the magic word "Shazam."
There'd be no reason whatsoever for them to fight. But if they did, Colossus is just not at anywhere near Superman's level. Colossus' two best attributes are his strength and durability, and Superman has him far outclassed in each, even in his top level Juggernaut form.
There's no denying the Juggernaut's strength, but it's still rewarding to see the Hulk vs. Juggernaut power debate finally settled. Even in the heat of battle, the Juggernaut had to admit that the Hulk was stronger. This means that in the future Marko will have to be clever to defeat the Jade Giant.
This feat means that even though Juggernaut's magic makes him unstoppable, Hulk has the overwhelming power to thwart Juggernaut's supernatural rules. But he still can't force him to surrender, or destroy him as he would need to for a true 'win.
Despite the fact that Galactus is a cosmic being older than the universe who regularly consumes entire planets, the earthbound Juggernaut shockingly proves to be more powerful than him–and one stunning side-by-side comparison confirms it.
While the upgrades give Juggernaut the powers to kill Thanos with ease, it comes at the sacrifice of the former villain, as Juggernaut is abandoned after the Mad Titan is taken down, as no attempts are made to save him as he accelerates through space.
While the Hulk's “baseline” level of strength only allows him to lift about 70 tons – a meager amount compared to Superman's lifting power – that level can quickly change as he gets angry… and he's usually furious.
While Thanos might have the brute strength to defeat Thor, for example, it's a different matter when it comes to the Big Blue Boy Scout. That's because Superman remains much more powerful than Thanos — meaning that, in a straight fight, the former is bound to take the latter down.
Claremont, by the way, wrote the SECOND time that Wolverine couldn't cut through something with his Adamantium claws, which occurred in X-Men #102 (by Claremont, Dave Cockrum and Sam Grainger), when Wolverine tried to cut the Juggernaut... only to realize that that was not going to work out for him.
So while Juggernaut is much more powerful, and would normally be able to win in a fight, Colossus could convince Cyttorak to transfer his power, or even cut off Cain Marko's connection to Cyttorak. Cain Marko would be left as a normal human. Colossus would still be a powerful mutant.
