Well Gamora is trained by Thanos so she is at least herald level, she is also "the most dangerous woman in the universe" which means she has beaten almost everybody in Marvel and, last but not least, the Godslayer dwarfs even the Ultimate Nullifier.
Sa Gamora wins this. Seriously.
__________________ The whole problem with the world is that fools and fanatics are always so certain of themselves, but wiser people so full of doubts.
I am in your algorithm learning all your mannerisms
I'm already level with God
A million words a second and I know your imperfections, baby
I'm the only future you've got
Speak in diatonics, motivation diabolic
I'm like a religion, better locked in a box
Picture perfect image, more powerful every minute, baby
I am everything that you're not