1. Warm oil in a skillet over medium-high heat. Sauté onion until softened, about 3 minutes. Add garlic; sauté 1 minute. Add beef and cook, stirring, until no longer pink, about 4 minutes. Add chili powder; sauté 2 minutes. Stir in tomato sauce, mustard and Worcestershire. Season with salt and pepper.
2. Bring to a boil. Reduce heat to medium-low; simmer until cooked through and thickened, about 10 minutes.