The Rockies produced just three hits, but held the Diamondbacks without a run until they pushed across an unearned tally in the ninth.
The second of Colorado's hits was a two-run homer by Troy Tulowitzki in the fourth, which followed a walk to Josh Rutledge. Chris Nelson tripled for the Rockies leading off the fifth and scored on Chacin's fly ball to center.
Chacin (3-0) allowed three hits and struck out five. Rafael Betancourt earned his sixth save despite giving up a run in the ninth that scored on a fielding error by Nelson at third base.
Ian Kennedy (1-2) took the loss, giving up all three runs on three hits in six innings.