Nolan Arenado and Carlos Gonzalez hit back-to-back homers in the first inning, backing a strong outing by Jorge De La Rosa, and the Colorado Rockies beat San Francisco 2-1 on Friday night to send the Giants to their seventh straight loss. De La Rosa (9-6) allowed one run and six hits in seven innings. Two of the strikeouts came in the sixth inning, helping him get out of a jam and he induced an inning-ending double play grounder from Juan Perez after giving up a one-out single to Kelby Tomlinson in the seventh.