Guthrie (2-1) baffled the Brewers on three hits, allowing only one run while walking three and striking out two.
Rex Brothers and Matt Belisle combined for a scoreless inning and Rafael Betancourt notched his fifth save with a 1-2-3 ninth for Colorado, which took the rubber match of a three-game set at Miller Field.
Cuddyer then drove a pitch into the left-center field gap, scoring both runners.
Milwaukee starter Yovani Gallardo held the Rockies to one run on six hits over seven strong innings.
Notable deaths of 2014 [PHOTOS]
Julius Randle breaks leg during NBA debut