The Justice League is home to some of the most powerful heroes in the world, including that of Batman and Superman, and while these two are often pitted against each other by fans, there's actually another League Member who could beat Superman without breaking a sweat.
While Superman is undeniably powerful, having such impressive abilities as super speed, heat vision, incredible physical strength, and nigh invulnerability, there's another League Member who has almost all of that and more. Martian Manhunter has Martian Vision, shape-shifting, super speed, super strength, and nigh invulnerability. The only serious difference between the two of them is how available their weakness is. Superman can really only be hurt by Kryptonite and magic, two things that aren't super easy to come by. Martian Manhunter on the other hand can have all of his abilities removed if he's exposed to fire. But despite this huge difference in their weaknesses, Martian Manhunter may still have the Man of Steel beat with no issue.
In Grant Morrison and Howard Porter's JLA #4 (1997) readers get to see exactly how dangerous Martian Manhunter could be for the Man of Steel if he so desired. A group of aliens called the Hyperclan have arrived at Earth, claiming that they came from a dying world and want to prevent humanity from making the same mistakes as them. They begin doing a lot of charity and other things, like fixing the Sahara Desert. Eventually, it's revealed that the Hyperclan are White Martians, the most dangerous aliens, and have been using mind control to win over the public. When Superman tries to confront their leader, he is quickly subdued with Kryptonite and captured, but Superman eventually realizes everything might not be as it seems.
The Martian Race Are Powerful Psychics
Telepathy and psychic abilities are some of the most powerful abilities the Martian race has, the ability to read minds, alter memories or even alter perceptions and that's exactly what happened to Superman. While bound and chained with Kryptonite overhead, Superman eventually realizes that there isn't any Kryptonite, he was merely tricked into believing there was. This caused his body to react accordingly and shut down. But once Superman realizes what's going on, he's able to break free and help beat back the White Martian invaders. This opens a big question though, if the White Martians were able to deal with Superman so-handedly, then there's no reason Martian Manhunter couldn't do the same. And considering Martian Manhunter's negative feelings toward Superman it could become a problem.
Superman is one of the greatest and most powerful heroes in the DC Universe, but many people have expressed concern about him becoming evil one day or being mind controlled, but if that should ever happen, there's no doubt that Martian Manhunter would be able to shut him down in an instant.