Can Adam Driver beat up Daisy Ridley?
I honestly don't know.
Could he knock her out in a single punch if she bothered to stand still and let him?
Again, I honestly don't know.
More to the point, though,
none of that matters for purposes of the film.
We're dealing with a film world where the following have literally been shown on screen:
- Yoda used the Force to lift a ship probably 30x his own size and weight out of a swamp.
- Yoda flipped and spun around like a spider monkey on crack to fight Dooku.
- Luke shot straight into the air about 40 feet to grab on to overhanging gear in the Bespin carbonite chamber.
- Numerous characters have pulled and thrown all manner of objects big and small through the air using the Force.
- Darth Vader crushed the windpipes of numerous people, including those he was literally just watching on TV who were in an entirely different part of the ship.
- Several characters have visions of the future as a result of the Force.
- At least one character has had abstract visions of a malevolent presence through the use of the Force (Luke in the cave at Dagobah).
- The Dark Side of the Force made at least two characters' eyes turn all red and evil-lookin'.
- Force-using characters have repeatedly used laser swords to block incoming blaster shots, and even reflect them back at the shooters.
- Even untrained individuals "sensed" things through the Force (e.g. Leia finding Luke on Bespin).
In The Force Awakens, we also see:
- Rey displaying hitherto unknown powers and abilities that astound even her, and whose origin she cannot explain.
- Chewie's bowcaster literally blow a Stormtrooper around 10 feet through the air and into a wall, as well as cause minor explosions near other troopers.
- Rey displaying her melee combat abilities using her staff.
- Kylo Ren harboring doubts of his own abilities.
- Kylo Ren apparently being reluctant to kill his own father.
- Kylo Ren taking a bowcaster shot to the gut and then having to fight Finn.
So, when Rey suddenly becomes imbued with the power of the Force, I find it
entirely believable that she could thereafter defeat an already-critically-wounded Kylo Ren.
Why? Simple.
The Force is, for all intents and purposes,
space magic. It doesn't obey the "rules" of the real world. Star Wars is not and never has been grounded in a reality that mirrors our own. To the contrary, it is grand space fantasy. Now, admittedly, it is grand space fantasy that has remained
familiar to us through a combination of storytelling tropes, expertly built props, and -- in some of the films, at least -- a kind of "weathered" or "lived-in" sense for the universe, but it has never, ever been "real" or striven for "realism."
Moreover, as I note above, TFA
did try to show its audience that Rey is (A) extremely powerful, (B) has an unknown limit to her power, (C) is uncertain of the source of her powers, (D) was hidden away for reasons that remain unknown to us, and (D) was fighting an already heavily wounded opponent.
So, in summation, there is zero reason why
Rey couldn't defeat
Kylo Ren, regardless of the fact that she's smaller, she's a woman, she's untrained in the use of the Force, etc.
It's space magic. Her abilities obeyed the rules created
within the universe. The film may not have effectively conveyed all of that to every audience member, but it
is there to be seen. If folks want to complain that the film didn't do
enough to explain Rey's abilities or contextualize why she could win in the fight against Kylo Ren, fine. But let's move on from the notion of "But he's bigger and stronger than her!" because, again --
space magic.