Not necessarily. Fire is the Martian Manhunter's main weakness, but there's a world of difference between being vunerable to something and automatically losing to it. Bullets can hurt Batman, but that doesn't mean a mook with a gun takes him out.
As far as I can tell, Evangeline uses ice, not fire. The MM would likely stick to fighting her, and let Doomsday deal with Mr. Firefists. Or he could use a mental attack.