If men and women are equals, and no distinctions in treatment are warranted, then treat her like you'd treat any man.

What happens when smaller guy punches bigger guy? Smaller guy usually gets hit. And nobody really gets upset.

So to me, given the prevailing assumptions about men and women, this should be a complete non story. Bar fights happen all the time and are nothing to get worked up over. Nobody would get worked up at all if this had been two guys punching each other. It only becomes a story if you accept that the law should treat men and women differently. Who's willing to argue for that these days?