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).
Thanos uses his durability to tank Surfers best shots. Surfer encases him in a black hole and Thanos escapes. Surfer gets upset and tries to go hand to hand and gets beat to death. (does the same to Superman)
Those scans don't show Surfer using any speed. Nor do they show him phasing to avoid Thanos's attacks. Why didn't Surfer up any black holes? Thanos does have problems with them. Why didn't Surfer us his time manipulation powers. Thanos doesn't have time powers. At least it shows that Thanos actually has to put energy around his hands to hurt Surfer. Thanos isn't that strong without the energy amping his strikes.
Being portrayed doesn't mean truth. Otherwise there would be no need for debate.
CIS off does matter. SS will not fight like a moron and actually use his powers and not be hindered by the writer in order to job to Thanos.
Thanos has serious problems with blackholes. That tactic alone would own him. Surfer can amp to levels to actually hurt Thanos well. Remember they are in outer space.
Just about any class 100 being can pimp smack Thor back.
Thor only weighs 700lb. and two beings with the same strength should be able to pimpsmack stun the other.