Preheat your oven to 375 degrees F (190 degrees C) and combine the ketchup and barbecue sauce in a small bowl. Set aside.
In a large bowl, combine the ground sirloin, tomato puree, toasted breadcrumbs, finely chopped yellow onion, salt, onion powder, pepper, and garlic powder. Use your hands to thoroughly combine the ingredients, but do not overwork the meat.
Transfer the meatloaf to a loaf pan, shape by making flat and even, then pressing your fingers down all the way along the sides (forming a well for any grease). Cover with foil and bake at 375 degrees F (190 degrees C) for 30 minutes.
Remove the foil (and drain off fat, if necessary), and drizzle the combined topping sauce (ketchup and barbecue mixture) down the center of the meatloaf. Do not spread. Return to the oven and bake for an additional 15-20 minutes, or until the center is no longer pink. Remove from the oven (drain fat again, if necessary) and serve immediately.