10 Most Powerful Beings Spider-Man Has Defeated
9. The X-Men - Secret Wars 1984
The thing about being Marvel's biggest icon is that it affords you a LOT of plot armor. There are tons of situations where Spider-Man just flat out should not be able to come out on top, at least not on his own. And yet because he is the most popular Marvel hero, bar none, he's pretty much guaranteed to win.
Case in point the original Secret Wars, where Spider-Man mops the damn floor with the entire X-Men.
When Spider-Man overhears Xavier discussing with the other X-Men that they cannot stay with the heroes due to them being mutants and thus outsiders from the human heroes (despite the other heroes giving them ZERO cause to believe they were unwelcome but whatever) Spider-Man immediately jumps to the conclusion that they're gonna go to the bad guys side and leaps in to fight them.
Contrived as it is, the fight between the X-Men and Spidey is legit incredible, with excellent choreography and every X-Men getting to show their stuff in the short time the fight takes.
Yeah Xavier wipes Spider-Man's mind at the end of this, technically handing the win to the X-Men, but considering that Spidey had worked his way through pretty much everyone else before then, I feel confident giving most of the win to him.