Miguel Montero belted a three-run homer in the first inning, and Josh Collmenter and four relievers made it stand as the Arizona Diamondbacks extended their home winning streak to a franchise-record 12 games Wednesday with a 4-2 victory over the Colorado Rockies.

The Diamondbacks maintained their six-game lead over San Francisco in the National League West.

Willie Bloomquist and Aaron Hill each had two hits and scored a run while Sean Burroughs added a pinch-hit RBI single for Arizona, which has won a season-high nine in a row overall.

After diving to tag out Dexter Fowler at the plate for the third out of the first, Montero launched his 14th blast of the year off Esmil Rogers (6-4) in the bottom half for a 3-0 lead. Colorado got within a run before Burroughs plated Hill with a two-out single in the sixth.

Collmenter (9-8) allowed two runs over six innings en route to his third win in four decisions. J.J. Putz worked a scoreless ninth for his 35th save in 39 opportunities.

Fowler homered for the second time in as many nights after going 100 games without one for the Rockies, who have lost nine of 11 on the road.