When it comes to the most powerful beings in the Marvel Universe, few top the individual strength that the Hulk and Juggernaut possess. However, when the two clashed after a very angry Hulk returned to Earth after being cast away by his fellow Avengers, the Juggernaut got absolutely walloped by the Jade Giant.
Hulk, known as Bruce Banner is his non-green form, is defined by his incredible strength, stamina, durability. Famously, the angrier he gets, the more powerful he becomes. He's taken on and defeated just about all of Marvel's strongest villains just on his pure strength alone. Meanwhile, Juggernaut is an X-Men villain (and sometimes hero) with his own super strength derived from a magical stone that made him invulnerable - including giving him forcefield powers that have stopped Mjolnir in its tracks. While the two brutes are set to go head-to-head in an upcoming series, they've matched up before in a fight that Juggernaut was absolutely destroyed.
In World War Hulk: X-Men #2 by Chris Gage, Andrea Divito, Laura Villari, VC's Joe Caramagna and Rich Ginter, the Hulk has returned to Earth after being sent into space by the Avengers in the Planet Hulk arc. When Hulk finds out that Charles Xavier was supposed to vote alongside the Illuminati and didn't, he heads to the Xavier Institute in order to find out if he would have sent him away. However, when Professor X is unable to provide a direct answer, Hulk tries to grab him before being halted by the X-Men. Hulk proves to be trouble for the superteam, wiping them out in a gruesome battle. Using the Cyttorak crystal to open a portal to teleport to the X-Men, Juggernaut (without his costume) emerges and lunges at the Hulk, punching him across the face. But, Hulk counters him with a knee, knocks him to the ground, and then delivers a punishing blow to the Juggernaut's back.
It's quite tremendous to see Juggernaut fall so easily. While his powers were being weakened by the Cyttorak crystal, part of the reason he was able to teleport (and get stronger) was because he agreed to do what the magical item wanted, which was "rampaging. Destroying. Killing."
In this particular fight, Juggernaut was simply overpowered. Hulk was already near full strength and made quick work of the fellow strongman. The fight is short and sweet, as Juggernaut is left trembling that "I'm the... the... j---" before Hulk delivers a finishing blow. It's hard fully grasp how powerful the Hulk's shot was, as not only did it take down Juggernaut but it caused the ground to break below him. The next time Juggernaut faces the Hulk, it's fair to assume he'll come with his armor and much more prepared - otherwise, he's going to get crushed again.