Lay the bacon onto a rimmed baking sheet lined with a baking rack. Bake until the bacon has rendered some of its fat but is still completely flexible and hasn't begun to brown, about 15 minutes. Remove from the oven and let cool 5 minutes. Raise the oven temperature to 450 degrees F.
Generously sprinkle the tenderloin with salt and black pepper.
In a small bowl, stir together the mustard, brown sugar, garlic powder and cayenne. Coat the tenderloin all over with the mixture.
Starting at one end, wrap the bacon strips around the tenderloin, overlapping them slightly so they are shingled.
Place the tenderloin on the baking rack and roast until 130 degrees F at the thickest point, about 17 minutes. Let rest 5 minutes, then transfer to a cutting board using a long offset spatula and tongs. Slice into 1-inch-thick rounds and serve.