As usual, Austin John Plays comes in clutch with a video guide.
https://www.youtube.com/watch?v=CFKYOLgrQ7A
I beat mine with Sylveon, but Azumarill is also a really good one to use. Just watch out for Hurricane possibly confusing your Pokemon, or give Sylveon the Covert Cloak to dodge that extra effect since it can heal itself with Draining Kiss.
https://i.imgur.com/PmF1p9q.jpg