In a small saucepan, combine catsup, water, soy sauce, vinegar, brown sugar, mustard, horseradish and garlic. Simmer for 10 to 15 minutes on back of grill. Moisten steak with water. Sprinkle evenly with half the tenderizer and pierce deeply with a fork. Repeat on other side. Grill steak five inches from medium-hot coals about 35 minutes, turning and basting frequently with sauce. TIP: Before barbequing, slash through fat on the outside of steaks at one-inch intervals to prevent curling. ----