Possibly Wonder Woman. I had seen a battle w/her vs Super man once before. & it might of been cause he's a gentleman, but he was getting clobbered. So WW vs Super Girl? I don't know if SS can do any better... maybe.
CHICK FIGHT!!! Shouldn't they be slapping each other, biting, pull hair and clawing eyes?
They are pretty much on par as far as power goes so I have to go with WW. She's the only trained fighter. But I would be rooting for who ever is losing just to keep the fight going because as long as no one wins we all win. XD