Denver, CO (Sports Network) - Dan Haren threw eight strong innings, and Adam Dunn knocked in his first two runs for Arizona as the Diamondbacks downed the Colorado Rockies, 6-2, in the rubber-match of a three-game set.

Haren (13-6) scattered seven hits and two runs while fanning nine and walking two for Arizona. Dunn, acquired from Cincinnati on Monday, had a two-run single in a five-run fifth inning for Arizona, which has won three of four after dropping four straight.

Chris Snyder and Chris Burke hit back-to-back homers in the fifth for the Diamondbacks.

Arizona remained tied with Los Angeles for first place in the NL West, after the Dodgers defeated Philadelphia later Thursday evening.

"We've got about 40 games left, and the only thing we can do is focus every time out," said Haren. "The season is a long grind, and here we are in the middle of August with a chance to go to the postseason, and I like our spot."

Glendon Rusch (5-4) surrendered five runs on five hits in 4 2/3 innings, with four strikeouts and two walks. Matt Holliday homered and Chris Iannetta, filling in for the injured Yorvit Torrealba, went 2-for-3 and knocked in a run for the Rockies, who have dropped four of five.

"It's a crazy game, we're not giving up yet," said Rockies second baseman Clint Barmes. "There's still a lot of baseball to be played so we're just going to go out and keep battling every day."

The Diamondbacks erased a 1-0 deficit and took control with a five-spot in the fifth. Mark Reynolds doubled to center to lead off the frame and, after a Chad Tracy groundout, Snyder and Burke went back-to-back. Snyder's two-run blast to left, his 11th, and Burke's solo shot, his first, boosted the D-backs to a 3-1 lead.

Arizona loaded the bases later in the frame, and Dunn came through with a two- run single off Matt Herges, giving Arizona a 5-1 edge.

Chris Young's RBI double in the seventh extended the D-backs lead to 6-1.

Holliday's leadoff homer to center in the eighth, his 23rd, pulled the Rockies within four runs. Jon Rauch worked around a leadoff single in the ninth, though, to close out Colorado.

Iannetta got the Rockies on the board in the second. After Ian Stewart singled with one out, Iannetta doubled with two down to right-center, plating Stewart for a 1-0 lead.