Scooter Gennett hit his first homer of the season, Buster Posey had a go-ahead pinch-hit double, and the visiting San Francisco Giants beat the Colorado Rockies 6-5 in Denver on Saturday night. Pablo Sandoval had three hits, Sam Coonrod (2-0) pitched one inning and Will Smith worked the ninth for his 27th save. Charlie Blackmon and Trevor Story homered and Daniel Murphy had three hits for Colorado.