Shalane Flanagan became the first U.S. woman to win the New York City marathon since 1977 today, finishing in a time of 2:26:53. It was the first major marathon win for Flanagan, who medaled in the 10,000 meters at the 2008 Olympics (a bronze later upgraded to silver) and holds several American records. She finished ahead of Mary Keitany, the defending three-time champion of the event. Mamitu Daska was third. The three broke away from a pack with about 5 miles to go in the 26.2-mile race. Flanagan fractured her back earlier this year, which forced her to drop out of the Boston Marathon. American women won the first six years the women’s open division was contested, with Miki Gorman winning in 1976 and 1977. …