Tyler Anderson allowed just two hits over eight scoreless innings in a second straight dominant start Wednesday night, when Chris Iannetta homered in the seventh inning to provide the only run as the Colorado Rockies completed a three-game sweep of the visiting San Francisco Giants with a rare 1-0 victory at Coors Field.The Rockies earned a 1-0 win at home for just the eighth time in the franchise’s 26-season history. It was their first 1-0 victory at Coors Field since a win over the Toronto Blue Jays on June 12, 2010.The Rockies have won six of seven to climb back over .500 (44-43) for the first time since June 8. Despite the sweep, the Giants have won 10 of their last 15 games.San Francisco has lost 15 of its last 17 games at Coors Field.Anderson (6-3) walked two and struck out nine in throwing eight scoreless innings for the second consecutive outing. He has lowered his ERA from 4.62 to 3.90 in the back-to-back strong starts.Anderson was even better on Wednesday than he was against the Los Angeles Dodgers last Friday, when he gave up four hits and issued a walk while whiffing eight in earning the win in the Rockies’ 3-1 victory.The Giants didn’t get a runner into scoring position against Anderson, who walked Buster Posey in the second and Andrew McCutchen in the fourth and gave up singles to Kelby Tomlinson in the third and Brandon Belt in the sixth. Anderson retired the final seven batters he faced, including four by strikeout.Iannetta, Anderson’s catcher, gave his batterymate the support he needed when he homered off Giants starter Andrew Suarez (3-5) with one out in the seventh. The Giants appealed the homer, but the replay showed Iannetta’s blast landing a few feet to the right of the foul pole and well beyond the left field fence.Wade Davis worked around a two-out single to McCutchen and a subsequent walk to Posey to retire Brandon Crawford on a long fly to right and earn his 25th save.DJ LeMahieu and Trevor Story had two hits apiece.Suarez took the hard-luck loss after allowing the run on five hits and no walks while striking out six over seven innings. He has allowed one run in each of his last three starts, a span of 18 2/3 innings in which he’s lowered his ERA from 4.70 to 3.92.