I keep on hearing about this fight where Validus is taking on Superman, Mon El and Ultraboy all at once. They eventually manage to KO him. I tried to look online to see if the fight has been posted anywhere, but doesn't look like it.

So I'll just search for the actual comic. Anyone knows which comic this happened in? *looks at rokk krinn*

I'm pretty sure it's Legion of Three Worlds a Final Crisis tie in

You mean the one with Superboy Prime?

It's definitely not that one as I read that one. This story is supposedly a silver age story.

From Wikipedia:
"The classic Validus possessed tremendous superhuman strength, enabling him to easily overpower even the Silver Age Superboy; in fact, on one occasion, it took the combined strength of Kryptonian-level heroes Superboy, Mon-El, and Ultra Boy just to knock him down,".
As for when & what issues & books, I'm not finding any info.