Koufax won two of the four in the sweep.
That was '63.
Not to be too glib about it, but if Mantle can't hit ya, ya can't be hit. If modern medicine, say, arthroscopic surgery, had been available then, who knows what Koufax could have done?
Koufax retired before I was born, so I never got to watch him play. But from his reputation, the closest recent pitcher has to be Greg Maddux. Him, I've seen, and when he's on, he's on. A 63-pitch complete game? That's so good it's rude.