Umar vs Zarathos

Both characters are from Earth-616

The fight is a random encounter

Both sides operate on standard power level

Both characters are blood-lust on and morals off

The battle occurs on a deserted planet/neutral area

Fight to the death

Probably Zarathos.

Dr. Strange only beat her with constant facial power. He was able to access the beauty of both her and her brother and defeat them with their own look.
Good Fight.
I think Ghost Rider would end up in a land full of debts paid in full in a big hurry.
Umar and Dormammu have a way of makeing it so.