Also like Thor, Superman is shackled and taken to the despotic ruler of this planet, who compliments him on his fighting spirit (“This one has the fire of a champion!” vs. “Well, he’s a fighter!”). Both heroes are then given an involuntary makeover and forced to wear a space gladiator costume, except Superman’s leaves a lot less to the imagination.
Next, Superman is told to fight the tyrant’s champion, a big green guy called Draaga, while being watched by a huge crowd of aliens in a giant arena, but he refuses and offers him a friendly hand … which Draaga just uses to sucker punch him. Pretty soon, Superman gets tired of being a punching bag and beats the crap out of his opponent.
DC Comics
DC Comics
So it’s basically the Hulk fight from Ragnarok but without the jokes. (Yes, the basic “Hulk as a space gladiator” idea and look are taken from Marvel’s Planet Hulk storyline, but that’s about it.)