Rarity is definitely a nice pony and she can fight when necessary but I definitely think she is a little outmatched here. Sasuke has the Sharingan at his disposal and a lot of speed and power even without it. Rarity will be caught in a genjutsu right away and thus she will be unable to fight for the rest of the match. No amount of telekinesis will be enough to bring her back from that. Illusions are just tough to stop. Sasuke wins.