Mix the minced garlic, salt, garlic powder, onion powder, paprika and pepper. Rub over the brisket.
In a small bowl mix the barbecue sauce, onions, Worchestershire sauce and liquid smoke (if using).
Place the brisket in a slow-cooker and pour over the sauce. Cook on low 10 hours or until the brisket is fork-tender. Pull the beef apart into strips.
Ladle the cooking liquid into a bowl or glass measuring cup and skim off the fat. Mix the juices with pulled beef. Serve on rolls.