The Rockies have won 20 of their last 21 games. They own a commanding 3-0 lead in the NLCS.
Matt Holliday's home run in the first inning off Arizona starter Livan Hernandez gave the Rockies a 1-0 lead. But Arizona's Mark Reynolds answered with a solo home run in the top of the fourth inning.
The Rockies' sterling defense turned three double plays in the first three innings in support of starting pitcher Josh Fogg. Fogg went six innings for the win. Jeremy Affeldt, Brian Fuentes and Manny Corpas closed out the D-Backs with three shutout innings of relief.
Hernandez was charged with four runs in his five and two-thirds innings.
The Rockies go for the sweep at home Monday night. Colorado sends out Franklin Morales against Micah Owings of the Diamondbacks.