The pilot stated that he made an uneventful flight to the destination airport and configured the tailwheel-equipped airplane for landing. During the approach he noted that there was no unusual gust or crosswind, and he touched down on the main wheels just after the runway’s identification numbers. On the landing roll, the pilot reduced the power to idle, and the tailwheel settled on the runway. The airplane encountered a sudden wind gust, raising the right wing. Despite the pilot’s attempts to maintain directional control, the airplane ground-looped to the right and departed the runway surface. The airplane continued into a ditch and the left gear collapsed, resulting in the left wing contacting the ground. The pilot reported that there were no pre impact mechanical failures or malfunctions with the airframe or engine.