Superman wins, but takes a severe blow to his reputation.
Well in a fight Jesus always turns the other cheek.....and then superman hits him again turning his other cheek. SO in essence you'll have the one turning his head side to side and one just punching the other one in the face.
Fun thought. Here's the issue with Jesus' powers...
On one hand, he's killed like any other man and has only been resurrected once. Perhaps there is some limit to his 'respawn' ability.
On the other hand, he's the son of god, right? If that's true, god himself would just erase superman from existence.... Poof, never existed... Nothing to see here.
Since they are both peace-loving do-gooders though, the more interesting question is how do we turn them against each other to the point of fighting?
right up Superman's tight little aluminum asshole.