BRUSSELS — Switzerland's Fabian Cancellara shook off Tom Boonen on the toughest climb of the Tour of Flanders and raced away to a solo victory ahead of the Belgian champion in one of the season's top one-day classics.

Lance Armstrong was close to the head of the pack up until the last 20 miles but did not cross the line among the leading finishers.

Cancellara broke away on the Wall of Geraardsbergen with 12 miles to go Sunday and the reigning Olympic and world time trial champion never gave Boonen a chance to get close again, finishing with an edge of 1.13 seconds. Belgian Philippe Gilbert was third.

Cancellara finished the 163 miles in 6 hours, 25 minutes, 32 seconds.