Roush Fenway Racing teammates Biffle, Kenseth and Edwards engaged in a thrilling run over the final 20 laps at Dover International Speedway, but Biffle made another textbook move to the outside late to pull away.
Biffle, the winner last week at New Hampshire, is tied for second place in the Chase points standings with Jimmie Johnson. Edwards has the top spot in the standings.
Kenseth was second, and Edwards third in a wildly successful day for Roush Fenway.
Kyle Busch had another miserable race and a blown engine knocked him out of the race. He finished last in the 400-mile race to drop to 12th and last in the Chase field.