Jeff Samardzija gave San Francisco a chance to grab momentum after a big offensive outburst a night earlier, but the playoff-hopeful Giants wasted it with a costly dud in a 2-0 loss to the Colorado Rockies on Wednesday night. Rockies right-hander Tyler Chatwood (12-9) struck out nine in eight innings and outdueled Samardzija (12-11), shutting down San Francisco a day after the Giants pounded 19 hits in a 12-3 win. San Francisco dropped to 1 1/2 games behind the Mets for the top wild card and remained a game up on St. Louis for the second spot after the Cardinals lost to Cincinnati.