Make a dry rub by combining chili powder, salt, garlic and onion powders, black pepper, sugar, dry mustard, and bay leaf. Season the raw brisket on both sides with the rub. Place in a roasting pan and roast, uncovered, for 1 hour.
Add beef stock and enough water to yield about 1/2 inch of liquid in the roasting pan. Lower oven to 300 degrees F, cover pan tightly and continue cooking for 3 hours, or until fork-tender.
Trim the fat and slice meat thinly across the grain. Top with juice from the pan.