Goku would Crush Superman in a duel....

Sun Wukong said
In "DC One Million" Superman spent around fifteen thousand years living in the middle of the sun. And I doubt that Superman is going to give Goku the courtesy of just standing around all day and collecting energy for the Spirit Bomb, unlike Frieza who was a moron, and Kid Buu who was being distracted by Majin Buu and Vegeta.

Would be pretty awesome fight to see Super Charged Superman vs Goku. He couldn't even use a Spirit bomb on Superman because superman is good. He'd have to use a dragon punch. Superman was beaten to death.

And if this were Pre-Crisis Superman, it wouldn't even be a fight. If he ever encountered something too tough to handle, he just made up a new power and saved the day.

Sounds like Goku just acquiring techniques with ease.