Preheat oven to 350 degrees. Fill bottom of roasting pan with carrots, onion and celery. Add half of tomatoes and water. Place the brisket on top. Cover brisket with the other half of the tomatoes. Cover pan with aluminum foil and slow roast in oven for 2-1/2-3 hours.
When brisket is tender, remove from oven. Remove vegetables and tomatoes and add to barbeque sauce, puree. Slice the brisket, place it in the puree and place back in oven for 15-20 minutes. Remove from oven and serve.
Recipe Courtesy of Rita's Burgers