How could a moderately powerful unicorn subdue, dispatch, or otherwise remove one or more of the Mane Six from a conflict?

5900311

Distract them, then simultaneously bash them over the head with a bottle of some sort carried by their telekinesis.

Or many bottles.

Or maybe a brick.

5900311 Split the group, then use a distance or some barrier to work their magic... knocking out Fluttershy or Applejack shouldn't be hard then.

5900623 That's a pretty solid plan.