Combine the soy sauce, lemon juice, garlic powder, chili powder, ground black pepper, and Worcestershire sauce in a bowl. Mix well.
Place the spare ribs in a resealable bag. Pour-in the mixture and then marinate for at least 6 hours.
Make the basting sauce by pouring the remaining marinade in a bowl. Add the ketchup. Stir.
Grill the spare ribs for about 8 to 10 minutes per side. You can rotate the ribs to prevent it from getting dry or burnt. Make sure to baste the ribs when rotating.
Transfer to a serving plate. Serve with pico de gallo.