Superman are two of DC's strongest characters, naturally leading readers to wonder which one would win in a fight. Superman himself has mentioned how he's afraid to fight Martian Manhunter. This is because of Martian Manhunter's telepathic abilities, which Superman is very suspectable to.
Normally the two are allies and never have a reason to fight, but, given their immense power, a conflict was inevitable. In one story, Superman finds himself in a sticky situation as Mongul makes a surprise appearance in his Metropolis apartment. In order to get the Man of Steel to do his bidding, Mongul captures Lois Lane and Jimmy Olsen. Naturally, Superman does everything in his power to save his friends. Superman is forced to do Mongul's bidding. This is where Martian Manhunter and the Man of Steel come face to face. Guarding the key that activates Warworld, Martian Manhunter stands his ground as Superman tries to retrieve it.
In DC Comics Presents #27 by Len Wein, Jim Starlin, Dick Giordano, Frank McLaughlin, and Jerry Serpe, Superman faces off against Martian Manhunter! Despite his recent worries, Superman is easily able to defeat Martian Manhunter. The two superpowered heroes have a fistfight before Superman uses one of his most dangerous powers, his heat vision. However, it must be noted that Martian Manhunter doesn't even attempt to use his powers before he is knocked to the ground. The choice to not let him use his telepathic powers was nearly definitely made so that Superman would have the upper hand and get the key to Warworld.
Without the key, the story couldn't progress. Therefore, Martian Manhunter was always going to be taken down, no matter what. If he were to have used his telepathy on Superman he could've easily stopped him from attacking. For instance, in Legends of the Dark Knight #10, Martian Manhunter is able to block Calendar Man from using his abilities. Superman without his powers is an easy target as he would essentially be a normal human. This is why present-day Infinite Frontier Superman fears Martian Manhunter or anyone with the ability to control people's actions.
All Superman does in this issue is use his heat vision to expose Martian Manhunter to his greatest weakness, fire. Retrospectively, looking back it's clear that DC has made Martian Manhunter much more powerful than he was initially depicted. Especially, seeing how underpowered he is presented in DC Comics Presents #27. Whereas, today, Martian Manhunter could put up much more of a fight and would probably have Superman on the run. Luckily, the two heroes are allies and will hopefully not run into any such troubles.
