The strongest punch Shazam ever landed while in battle makes Superman look like an absolute weakling. Billy Batson became the superhero Shazam, or Captain Marvel as he is also known, after he was taken to the Rock of Eternity. There, the Wizard gave him the mystical, godlike powers of Shazam and from that day forth he became one of the most powerful beings in the DC Universe, challenging even the near limitless might of Superman. While Shazam’s strength has always been thought of as being comparable to the Man of Steel’s, Shazam’s strongest punch says otherwise and puts the magically-powered hero leagues ahead of the Kryptonian.
In Shazam!: The Monster Society of Evil #4 by Jeff Smith, the evil villain Mr. Mind invades earth with three giant robots in an effort to take over the planet. Mr. Mind is doing this with the help of another Shazam villain Sivana. When all three giant robots are gearing up to launch their final strike against earth, and when all hope seems lost, Captain Marvel delivers a debilitating blow against the most powerful of the three titans, one Superman could never hope to accomplish.
Before attacking the robots with everything he had, Shazam fell victim to the interdimensional magic within the mechanisms. Mr. Mind used the Rock of Eternity to travel from his dimension to earth, and whenever Billy Batson transforms into Captain Marvel within or around the Rock of Eternity, his powers become erratic and unpredictable. In this case, Billy was confined by one of the robots but transformed into Shazam anyway, and the magical paradox he caused made him just as giant as the robots themselves when he became Captain Marvel. Matching them in size and with all of the energy he could muster, Shazam used the strength of Hercules and the power of Zeus to punch one of the robots so hard that he created a black hole, one which sucked away all of his enemies. Shazam literally punched through reality, by accident, which is something Superman has never even come close to doing under normal circumstances.
While Superman has never achieved such an unbelievable feat of strength, he did come pretty close once. In Justice League #25 by Scott Snyder and Jorge Jiménez, Superman super charges himself by flying through multiple suns and delivers a dimension-shattering punch upon the villain the World Forger, breaking the multiverse he created. Superman’s attack in Justice League #25 was impressive, but he needed the energy boost of multiple suns in order to pull it off, and even then it wasn’t as impressive as what Shazam was able to accomplish.
Completely by accident, Shazam punched a hole through reality and created a black hole that led to another dimension, a punch that is easily his strongest one to date and one that makes Superman look weak.