SAPPORO, Japan, Aug 7 (Reuters) - Kenya"s Peres Jepchirchir won the Olympic women"s marathon in Sapporo on Saturday, claiming the country"s second consecutive gold medal in the event. Fellow Kenyan Brigid Kosgei took silver and Molly Seidel of the United States took bronze. Kenyans Kosgei, the world record holder, and world champion Ruth Chepngetich had been favourites to win on Saturday. But it was two-time world half marathon champion Jepchirchir who came out on top after breaking out of a virtual tie with Kosgei at the 40km mark. Jepchirchir finished with a time of 2:27:20, 16 seconds ahead of Kosgei. Seidel, competing in just her third marathon after moving up from shorter distances, finished 26 seconds behind. Battling hot and humid conditions, Chepngetich dropped out around the 30km mark, while Israel"s Lonah Chemtai Salpeter dropped out at the 38km stage after looking like a strong contender for bronze.