Preheat oven to 200°C (390°F). Cut the pork fillets into pieces, about 8 pieces of the same size, and brush them with extra virgin olive oil. Wrap the pork tenderloin in pancetta slices, put a sprig of thyme over each piece and secure it with a piece of butcher's twine. Set aside.
Cut the potatoes in halves or quarters, depending on their size, leaving the skin on, then arrange them in a baking pan with the unpeeled garlic cloves. Drizzle with extra virgin olive oil and season with salt and pepper. Stir to mix thoroughly. Roast the potatoes in the hot oven for about 20 minutes.
After 20 minutes, add the pork tenderloin and the tomatoes and roast for 20 more minutes, or until the pork is well cooked and the potatoes are golden. Make sure that pork, potatoes and tomatoes have enough space in the baking pan, as to roast them evenly.