Girls, Could a sister beat a brother in a fight?

My sister and I argue a lot and we don't usually actually physically fight and haven't since I have hit puberty. I have become way taller and stronger than her and she is tiny and weak next to me now but she says she could still easily beat me if we fight, do you think she is right? She said she will fight me at any time I want still and says she could still beat me within seconds and I would be crying on the floor.
How would she do this? Have you beat your brothers in fights? How did you do it?
Girls, Could a sister beat a brother in a fight?
Post Opinion