Combine marinade ingredients and pour over duck breasts.
Cover and refrigerate for 4 – 12 hours.
Combine basting sauce ingredients in a bowl and mix well.
Place duck breasts on a well-oiled medium-hot grill and cook breasts 2 –3 minutes per side or until medium-rare.
Baste with basting sauce during cooking, reserving 1/4 cup of the sauce to drizzle over cooked breasts.