It’s another slow crime day in Metropolis on the cover of Superman 46 (May/June 1947).
This story, by Siegel, Sikela and Roussos, is called “Mr. Mxyztplk goes to College,” but aside from the first page, in which he enrolls, the story is all about Mxyztplk playing baseball.
As the imp’s magic gives his team an unfair advantage, Superman approaches a rival college about playing for their team. He is completely incensed that anyone would use magic to besmirch the sacredness of baseball.
Once the set up is out of the way, it’s all fun and games with the two playing baseball, using their abilities to ensure a lively match.
Superman wins by rounding the bases from underground, and defeats Mxyztplk the other way by getting him to cite from the rule book, into which Superman has placed his backwards name.