Preheat grill for two zone or direct/indirect method.
Trim extra fat off bavette steak and pat dry. Combine salt, pepper, and garlic powder and sprinkle generously over both sides of the bavette steak.
Place the steak over direct heat for two minutes or until you see a sear develop. Flip the steak and place back over direct heat for another two minutes or until you see a sear develop on that side.
Move the steak to indirect heat, and cover. Check temperature after five minutes and remove from the grill when the temperature of the thickest part of the steak reaches 125 to 130 degrees Fahrenheit.
Let the steak rest for 10 minutes, then slice against the grain. Plate, and drizzle sauce over the steak.