It was the Diamondback's fourth straight victory and the Brewers have dropped four in a row after winning their first game of the season.
Kubel's homer came as part of a three-run fourth that put the Diamondbacks in front 4-2. Goldschmidt's blast was hit in the fifth and Aaron Hill tacked on another solo shot in the eighth.
Patrick Corbin (1-0) went six innings to collect the win, allowing two runs on eight hits.
Mike Fiers (0-1) was tagged with the loss, surrendering six runs on nine hits over five innings.