Score steak with knife on both sides. Pour combined remaining ingredients over steak. Cover; marinate in refrigerator several hours or overnight, turning once. Place steak on greased rack of broiler pan or greased grill.
Broil or grill, uncovered, over hot coals 15-20 minutes or until desired doneness, turning and brushing with barbecue sauce mixture after 10 minutes. To serve, carve steak across grain, with slanted knife into thin slices.