Even if Superman isn't the most powerful hero in the DC Universe, his strength and will power have made it rare for the Man of Steel to lose a fight. Superman has even defeated some of Marvel's strongest heroes. Both Spider-Man and the Hulk fell to Superman's might. Though fans have spent decades speculating who among Marvel's mightiest heroes could best Superman, the answer came in an obscure crossover from the 90's. In DC/Marvel All-Access #1 Venom wins a fight against Superman.
Understanding this strange crossover requires understanding its main character Access. Access is the only character not in the public domain owned by both Marvel and DC. Though born in the Marvel universe, he gains the power to shift between that universe and DC's during a fight between the two. After the two universes merge and then separate again, Access is left as the sole being responsible for making certain everyone stays in their universe.
All-Access starts with the titular hero sensing that Venom is out of place. In Metropolis, Venom demands a young woman tell him where he is. Just as Venom steals the woman's glasses to make a bad joke, Superman slams into Venom and sends him through a brick wall. All it takes is Superman mentioning the similarities between Spider-Man and Venom's costumes for Marvel's most well-known anti-hero to go berserk. Venom blinds Superman with webbing, grabs him by the cape, and throws him into a bus with no effort. Though Superman does manage to land a blow or two, Venom easily beats him by using his black webbing to go down Superman's throat and close his airway. Just before Superman suffocates, a third player joins the fight as Access brings Spider-Man into the DC Universe.
Enraged by Spider-Man's presence, Venom flees. After Superman pulls Venom's gunk out of his eyes and throat, he and Spider-Man pursue Venom. Even with Spider-Man's help, Superman struggles against Venom. The violent vigilante easily juggles the two heroes. As Venom prepares to finish off the two most popular heroes in the world, Access arrives with a sonic cannon that knocks him out, ending his rampage.
While all of the Marvel and DC crossovers have involved Superman brawling with some of Marvel's strongest characters, Venom remains one of the few who managed to win. The fact that Venom beat Superman is strange considering characters as powerful as Juggernaut and Doctor Doom could barely put up a fight. As with most things in the comic industry, the story was more dictated by fan expectations and industry trends than the characters' abilities. Given their power sets, Superman should have no problem defeating Venom his heat vision, or a single high-powered clap. The problem was that Venom was just too popular. As a character somewhere between hero and villain, Venom exemplified the dark age of comics. All of it adds up to making DC/Marvel All-Access #1 a fascinating artifact of its era.