Preheat a barbecue for medium-high heat then lightly oil the grate.
Sprinkle 1 teaspoon garlic powder on a chicken breast then season with salt and pepper. Lay one rosemary sprig on the chicken breast. Wrap the bacon around the chicken to hold the rosemary on. Secure the bacon with a toothpick or an additional thick rosemary stem.
Cook the chicken breasts until no longer pink in the centre and the juices run clear, 8 minutes per side. Stay near the barbecue to put out any wee fire from the bacon. Remove the toothpicks before serving.