Silver Surfer (unhindered) vs. Thanos (normal)
This is CIS off Surfer. He will use his top speed and reflexes in battle. He would use all of his powers at his disposal. That means he will use shields, phasing through attacks, creating black holes, using force fields (like he did to trap Thor's hammer for a moment), amping to higher levels, etc.
Thanos will fight as his normal self in comics.
Fight is to ko or death (whichever comes first).
Battlefield is in outer space within a cubic AU of volume. A medium mass star also lies within this battlefield.
Who wins and why? You must answer why who wins and not just who wins. Try to give a scenario of how the fight will go (give some details of some things that could mostly likely happen).