Warning: contains spoilers for Superman: Son of Kal-El Annual #1!
The most well-known enemy of DC's Superman is the super-genius Lex Luthor, who is widely known in the DC Universe as one of, if not the smartest humans on Earth. Luthor is immensely prideful and egotistical, but he has the intelligence to back up his boasting, frequently creating radical inventions to save lives (if only to make a profit, or to create a method to destroy Superman). But in Superman: Son of Kal-El Annual #1, the self-proclaimed smartest man on Earth was outsmarted by the son of a man from Krypton at his signature game.
Lex Luthor is known as a great criminal mastermind, but he's frighteningly smart, and constantly combines his two passions to rise above everyone else on the planet. He's memorably even cured cancer in Superman #149, but merely as one part of a plan to destroy Superman. Since then, a new Superman has arrived in Metropolis - Jonathan Kent, Clark Kent's son - and Luthor treats him the same way he treated the past Man of Steel: with disdain at best and violence at worse.
In Superman: Son of Kal-El Annual #1, Jonathan Kent and Luthor play a simple game of chess, with comparatively low stakes - Luthor will take down a massive sign of his own name that casts a shadow over the Daily Planet building if Jon wins - but a victory for either man is a massive gain. For his part, Superman is furious that people like Lex Luthor, with his wealth and resources, do very little to solve the problems of the Earth - namely the climate change crisis facing the world today. Clark Kent refused to play Luthor's games of chess...but Jon is not his father. He plays, and wins. Luthor can barely contain his anger.
In seven minutes before the game, Superman read every chess book at the Metropolis library, including Luthor's own games since he began playing at six years old. He noticed Luthor relied on a single strategy that he had used for years. But the real reason Luthor lost was, in Superman's own words, "...you could have played with more caution, but you underestimated me." This is always Luthor's downfall: his habitual hubris and harmful hedonism. In a way, despite Superman's powers, Luthor always underestimates Superman's intelligence. Combined with his incredible speed and ability to research faster than Luthor ever could, Superman is deadly.
Luthor begrudgingly agrees to Superman's terms. Perhaps shockingly, Luthor's loss wasn't part of some grand gambit; he didn't deliberately decide to be defeated, as is the case with so many "mastermind" style villains. The Son of Kal-El just won his first major victory against Lex Luthor in a way that the original Superman never could - by beating a genius at his own game.