The Rockies jumped all over Brewers starter Randy Wolf, scoring four runs in the first inning, and eventually took an 8-2 lead into the seventh.
The Brewers (52-63), scored once in the seventh to cut their deficit to five, then in the top of the ninth, an RBI double from Martin Maldonado, and RBI singles by Jonathan Lucroy and Norichika Aoki made it a two-run game at 8-6.
However, with runners at second and third and one out, Rickie Weeks flew out to center, then Ryan Braun capped an 0-5 night by flying out to left, ending the contest.
The defeat is Milwaukee's 13th in 14 road games since the All-Star break. They will try to avoid a sweep on Wednesday afternoon at 2:10 at Coors Field. Mark Rodgers will start for the Brewers.