A topic like this could only exist on /a/
Gurren Lagann. Pitting a Super Robot with some form of mecha energy(Getter rays, spiral energy, g stone, power of evolution, photon rays etc.) that can solo massive alien armies if need be against a mech that can only handle a few grunts.
It's not even a competition.
A better fight is:
Dancouga(original) vs. New Getter vs. Gurren Lagann(winged)
All three have power of evolution is it's fair