CASTELFIDARDO, Italy — Oscar Freire sprinted to victory in the sixth stage of the Tirreno-Adriatico race Monday, and Fabian Cancellara retained the overall lead. The Spaniard won in 4 hours, 46 minutes, 44 seconds on the 122-mile ride from Civitanova to Castelfidardo in central Italy. The three-time world champion overtook Filippo Pozzato and Danilo Di Luca in the final sprint to claim his ninth career stage in the race. He won it in 2005.