SAN FRANCISCO -- 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.
In a game that began with a hovering mist above the field on a cool Bay Area night -- with first-pitch temperature 55 degrees -- Samardzija struck out a season-high 11 in six-plus innings of his final regular season start. He allowed seven hits and two runs, walking one.
Pinch-hitter Kelby Tomlinson doubled leading off the ninth against Rockies closer Boone Logan, who then allowed Brandon Belt's two-out infield single.Adam Ottavino retired Buster Posey on a groundout to third to end it for his sixth save.
The Giants' lone runner to reach second before the ninth was Angel Pagan on a wild pitch in the second. What a contrast from San Francisco's free-swinging performance Tuesday, when it produced 10 extra-base hits with three home runs, four triples and three doubles.
Twice baserunners were caught stealing and the Giants grounded into a pair of double plays. They know they have serious work to do in order to keep alive a streak of World Series championships in even years this decade: 2010, '12 and '14.
Samardzija has struck out nine or more Colorado batters in each of his past three starts against the Rockies. With runners on first and third and one out in the sixth, Samardzija induced an inning-ending double play by Nolan Arenado.
Chatwood dazzled -- and that has been the norm for him away from Coors Field. He allowed three hits and walked two.
He is 8-1 with a majors-best 1.69 ERA in 13 road starts, and he is 3-1 in six career outings at AT&T Park. Chatwood's road ERA is the lowest in franchise history for pitchers with at least 80 innings.
After allowing Conor Gillaspie's leadoff single in the third, Chatwood retired the next 11 batters in order before Brandon Belt drew a leadoff walk in the seventh.
In Thursday night's series finale, San Francisco will try to win just its second home series since the All-Star break and fourth series overall in 22 over the second half.