Superman wrestled one of the Four Hosts of the Presence
Superman's power levels are more variable than any other character's. One week he's putting Almighty God in a headlock, the next he's struggling with Toyman's robots. Whatever.
And Junior was the kid of the supervillain community's Charles Manson. I don't think it's unreasonable that she'd grow up to be especially scary, even by crazy supervillain standards.