So much for first impressions. The Colorado Rockies played nine innings of insipid baseball in their home opener yesterday, falling to the San Francisco Giants 7-0. The Rockies could muster just four hits on the day against Giants starter Barry Zito, who went the distance and became the first left-handed pitcher to shut out the Rockies at Coors Field since 1997. But offense was hardly the only aspect of the game in which the Rockies utterly failed. Starting pitcher Jhoulys Chacin gave up four runs on four hits and five walks in just four innings of work. Carlos Gonzalez and Troy Tulowitzki both made errors that helped the Giants score three more runs in the fifth frame. The Rockies, who have lost three straight after their Opening Day win, have today off to lick their wounds before resuming their series with the Giants tomorrow night.