Now that most of the epic comic book fights ever published have been adapted to the big screen, fans and creators alike are on the lookout for the more unheralded matchups from comic continuity - those that might show up in the next few phases of superhero cinematics. Followers of the genre have traditionally debated who would win a superhero fight between their favorite characters, but there are unexpected results out there in the history of both DC and Marvel Comics that make prognosticating difficult.
Generally speaking, it’s a good rule of thumb never to count out a character starring in their comic book - and there are countless upset victories against some of the most powerful villains to prove it. Squirrel Girl has taken down her fair share of mighty opponents, and there are several instances in which one scrappy street fighter overpowers a notoriously strong team. Depending on who is writing the comic, any character can theoretically beat any other character on any given day - it’s all just a matter of crafting the right circumstances.
Daredevil is used to defying the odds - but at the end of the day, he's still mostly an ordinary human with no superior strength or speed. That's what makes it such a shock that he's able to battle an entire Avengers roster to a standstill - especially when that roster contains Hercules, an actual Greek god.
In Daredevil #155, Matt Murdock shows up at Avengers Mansion looking for revenge against Black Widow - and he doesn't care who gets in the way. He stomps all over Captain America, the Beast, and Hercules - leaving each of them in a state of unconsciousness. Fortunately for Black Widow, Daredevil regains his self-control before he moves on to her.
Heroes in Crisis features a detective mystery in the DC Universe with Harley Quinn as one of the main suspects. When DC's holy trinity - Batman, Superman, and Wonder Woman - track Harley down for questioning, she doesn't go quietly. Instead, she fights the world's finest heroes to a standstill.
Harley Quinn uses a combination of athleticism and ingenuity to close the power gap between her and the most prominent members of the Justice League. She snags Wonder Woman's Lasso of Truth and uses it to undermine Batman - and then she makes him tell her where he keeps the Kryptonite in his Bat-belt. In the end, Harley escapes, and the trio is left with significantly more questions than answers.
Ka-Zar is essentially Marvel Comics' answer to Tarzan - a non-powered human who grew up in the prehistoric jungles of the Savage Land. When he discovers in Ka-Zar #11 that Thanos is causing havoc in his homeland, he takes him on - and somehow, he walks away victorious.
There are some extenuating circumstances in this matchup. Much of Thanos's energy is being fed into a terraforming machine at the time, so he's not at his best. But that still doesn't explain why an ordinary human can take on one of the strongest beings in the universe. Ka-Zar enjoys a lengthy battle with Thanos that culminates in him booting the Mad Titan into a volcano - though later, this particular Thanos is retconned as a defective clone, robbing Ka-Zar of his upset.
The mutant Domino is most recognizable for her role in Deadpool 2, where her luck-based powers and martial arts prowess is on full display. The Red Hulk, on the other hand, is an even stronger version of the Hulk who has defeated enemies as powerful as Thor, the Watcher, and the Grandmaster - yet he can't beat Domino in a one-on-one matchup.
Avengers vs. X-Men features head-to-heads between the members of each team, and Domino draws the unlucky straw of facing off with the Red Hulk. Despite the obvious power imbalance, she uses her luck powers to conveniently strike the Red Hulk's "pressure points" and take him out - even though his muscles are so dense they can withstand blows from Mjolnir. In other words, Domino must have been quite lucky.