Ironically, Gladiator's best showings against Thor are non canon because they involve future or alternate reality versions of the character : Future Gladiator in the "Black Celestial Arc" FF storyline goes toe to toe with Thor despite being exhausted and despite Thor and crew moving at hyper light speeds due to Reed's equipment, an alternate reality Gladiator is summoned by Zarko to take on Thor because Zarko thinks he'll go insane and take over the planet. Gladiator owns Thor and Thor Girl had to jump in to help.