Warning! Spoilers for Infinite Frontier #5 by DC Comics below
DC's version of Iron Man just showed how easily Tony Stark could defeat Superman if given a chance. In Infinite Frontier #5, Machinehead - DC's pastiche of the Avenger - just took down President Superman by acquiring his biggest weakness, Meta-Nite. The moment shows that while Superman might seem unbeatable at times, someone as smart as Stark could stop him if needed.
Machinehead debuted in Multiversity #1 as part of the Relaliators, a team resembling the Avengers. Created by Grant Morrison and Ivan Reis, the Earth-8 superteam had characters inspired by Marvel characters. Team members included Bug (Spider-Man), a rage-filled monster named Behemoth (Hulk), and a genius inventor named Machinehead. His identity has never been revealed, but the hero was disfigured during a war and watched his world change for the worse following Flashpoint. Machinehead joined the Justice Incarnate to protect the Multiverse from the most dangerous threats but revealed he created his own evil Injustice Incarnate to ensure each Earth was separate from one another.
In Infinite Frontier #5 by Joshua Williamson, Paul Pelletier, Tom Derenick, Jesus Merino, Raul Fernandez, Norm Rapmund, and Romulo Fajardo Jr, Machinehead unleashes his Injustice Incarnate on the greatest heroes across the Multiverse, including the Justice Society of America. As President Superman attempts to save The Flash, Machinehead attacks. He reveals Earth-0 is the cause of their hardships, as the Flash going back in time to save his mom had grave side-effects to Earth-8. Next, Machinehead tells President Superman he killed Lex Luthor and learned the Man of Steel's biggest weakness, Meta-Nite. Finally, Machinehead knocks President Superman to the ground using the resource and tells him he wishes they could have worked together.
While Superman would undoubtedly obliterate Iron Man in a one-on-one fight based on pure power, Machinehead shows how the Marvel hero could win. Superman is vulnerable to two things: kryptonite and magic. Readers have seen Superman fall to Batman in a kryptonite-powered Justice Buster. MCU viewers have also seen Tony Stark create elements and figure out time travel to fight his biggest problems. Iron Man has come up with suits to fight the Hulk and literal gods. He could definitely follow Machinehead's lead and build something infused with kryptonite to stop Superman if need be. Iron Man thrives at attacking and exploiting weaknesses.
What makes Tony Stark such a great and (at times) frustrating character is that he's seemingly got a solution for nearly every problem thrown his way. Like Batman, if given time to prepare, Iron Man could figure out how to stop Superman. Machinehead just showed how it would be possible - even if it was a different Superman.