Why do all these battles have Superman in them? The instant you put Superman in, you know the opp is going to lose. His only weakness are things from his planet of Krypton such as Kryptonite and Doomsday.
Superman comes flying in like a boss. Superman uses heat vision. Cyclops blocks it with his. Superman then uses superbreath. Storm stops it with weather control. Superman uses superspeed and beats up everyone. His strength lets him rip Colossus into shreds. Last people standing are Wolverine, but ko'd and relying on regen, and Nightcrawler who teleported away the instant he saw Superman coming. Unless Nightcrawler goes to teleport to some Kryptonite, Superman chases him and kills him because he is that fast.
If this is just 1v1 and no one is allowed to help each other in battle - Blue Beetle beats Spiderman. Captain America vs Batman ends in a draw. Unbreakable shield is just too unbreakable, but instant he throws it Batman goes in for the kill. Giant Man vs Atom Smasher. Draw and ends into a fist fight. Atom Smasher wins from more knowledge in close range combat. Black Canary beats Black Widow instantly. Just keep screaming. Iron Man vaporizes or uses some Stark Atomic Bomb and kills Steel. Draw. Both turn invisible and hide in shadows like babies. Green Arrow vs Hawkeye. Draw. They both fire arrows at each other at the same time and die.
Basically Blue Beetle just comes back and beats everyone that are drawn afterwards.