Bring a large pot of heavily salted water to a boil. Add pasta and cook until 2 mins shy of al dente. Drain pasta, reserving 1/2 cup pasta cooking water.
Meanwhile, heat a large skillet over medium-high heat, add olive oil and heat. Add bacon and cook until it starts to render its fat, about 2 minutes. Add garlic, red pepper flakes and a large pinch of salt and pepper and cook until fragrant. Add tomatoes and cook until they burst, turn golden at the edges and shrivel up slightly, about 5 to 8 minutes.
Add pasta to pan and toss with tomato-pancetta mixture; if the mixture looks dry add a little pasta cooking water a few tablespoons at a time. Cook over high heat until the pasta finishes cooking in the sauce. Add the butter and toss until it melts and coats everything. Add basil.