The pilot reported that when the tailwheel equipped airplane approached the airport, the wind was variable from 290 to 050 degrees, gusting to 20 knots. While on a two mile final, the tower controller reported the wind was 290 degrees at 7 knots. The airplane touched down on the main landing gear with no noteable crosswind. As the tailwheel touched down, the airplane suddenly veered to the right; the pilot corrected with left rudder and the airplane veered hard to the left. The pilot attempted to add right tudder and brake, but to no avail. The airplane exited the left side of the runway onto the dirt when it nosed over and came to rest inverted. The upper wing and rudder were substantially damaged. Postaccident examination by a Federal Aviation Administration inspector did not reveal any anomalies with the airplane that would have precluded normal operations.