Denver, CO (Sports Network) - Jason Giambi's pinch-hit two-run homer in the bottom of the ninth lifted Colorado past the Arizona Diamondbacks, 4-2, for the Rockies 10th straight win.
Ryan Spilborghs added a two-run pinch-hit double in the seventh for Colorado, which has won 13 of its last 15 games at Coors Field. Colorado is two games behind San Diego for the top spot in the National League West. The Padres are currently in action against second-place San Francisco.
After Huston Street (3-4) tossed a perfect top of the ninth, Jonathan Herrera reached on an error with one out off Sam Demel (1-1). After Clint Barnes went down on strikes, Giambi stepped in and crushed a 1-1 slider over the center field fence for the dramatic win. It was Giambi's eighth walkoff with for the 39-year-old's career.
Rockies starter Jhoulys Chacin lasted only four innings after allowing two unearned runs on five hits, with four walks and as many strikeouts.
Miguel Montero had an RBI double and Adam LaRoche added a sacrifice fly for the Diamondbacks, who have dropped seven of eight.
Arizona starter Ian Kennedy worked six shutout innings, yielding two hits and three walks while fanning six.
Arizona opened the scoring with two runs in the third. Kennedy started the inning with a single and made it to third on Chacin's throwing error with one out. After Kelly Johnson drew a walk, LaRoche chased in a run with a sac fly. Montero followed with an RBI double.
The Diamondbacks had a bases loaded and two out threat turned aside in the fourth when Johson grounded out.
Meanwhile, Kennedy retired 15 in a row before giving up a two-out double to Carlos Gonzalez in the sixth.
Blaine Boyer replaced Kennedy to start the seventh and allowed runners to reach first and second on walks. Then with two out, Spilborghs' shallow pop went off the glove of shortstop Stephen Drew for a double bringing in both to tie the game. Eric Young Jr. then reached on an infield single with Spilborghs taking third.
Aaron Heilman entered out of the Arizona bullpen and struck out Dexter Fowler to prevent further damage.
Both teams had threats turned aside in the eighth.
Rockies catcher Chris Iannetta left the game in the second inning with a right calf strain...Colorado, swept the Diamondbacks for the second time this season at Coors Field, with the first coming from May 25-27...The Rockies have now won 11 of the last 13 at home versus the Diamondbacks...Arizona third baseman Mark Reynolds was ejected by home-plate umpire Gerry Davis for arguing in the top of the seventh.