Arrange ribs in shallow roasting pan. Distribute lemon and onion slices over ribs. Pour in water. Cover with foil and bake in a 350 degree oven for 50-60 minutes.
Meanwhile in a small saucepan over medium heat, combine catsup, brown sugar, vinegar, mustard, chili powder, salt, paprika and Worcestershire. Cook uncovered until sauce thickens slightly. Set aside.
Remove ribs from oven, lift off and discard lemon and onion slices. Lift out ribs and cut between each rib bone. Discard pan drippings.
Return ribs to pan in a single layer with meaty sides up. Brush all over with barbeque sauce using about 1/2 of the sauce. Return ribs to oven and continue baking, uncovered, brushing often with remaining sauce, for 30-35 more minutes or until meat is well browned and fork tender.
