Mix together dry rub and coat both sides of meat. Pour half your bottle of bbq sauce inside slow cooker. Lay brisket on top with fat pad on top.
Pour remaining sauce on top of meat. Close lid and set to low for 8-10 hours. 8 hours will yield a piece you can slice against the grain. If you want pulled beef you will likely need closer to 10 hours to pull it apart, put back into the sauce in the pot to coat.
** timing will depend on thickness and size of piece
If you want to caramelize the sauce on top a bit on the top you can remove from slow cooker and set on a baking sheet. Put into a preheated oven at 400 degrees f for about 10 minutes or until the top is browned.
If left whole, remove from pot, let rest for 15 minutes before slicing against the grain and serving.