How supergirl is nearly as strong as supes and doesnt hold back much,supes can take wonderwoman in a serious fight and i believe supergirl could as well.
Not really, its been shown that clark is much stronger than Supergirl. Now I wont negate the fact that Superman can take WW in a fight, but WW is much closer to Superman than Supergirl is... durability, strenght and speed wise, but WW>Clark in fighting skills. Plus WW's superior fighting skills should help her in this fight.