Milwaukee (3-2), has now won the first two contests of a four-game series.
The Brewers scored five runs in the first inning against Cubs starting pitcher Paul Maholm. New Milwaukee shortstop Alex Gonzalez crushed a three-run homer to lead the way in the frame. Jonathan Lucroy added a solo homer later in the contest.
Chris Narveson (1-0) worked five innings to pick up the win. Francisco Rodriguez retired the final two Cub hitters to receive his first save as a member of the Brewers.
Milwaukee and Chicago will play day games on both Wednesday and Thursday at 1:20 P.M. to complete the series.