Mark Reynolds added a solo shot in the eighth as the Brewers won for the fourth time in five games. Matt Garza (8-8) allowed one run and four hits in six-plus innings.
Milwaukee remained 1 1/2 games back of Pittsburgh for the second wild card in the NL.
Todd Frazier hit his 26th homer in the sixth for Cincinnati, which has lost five of its last six games against Milwaukee. Mike Leake (11-12) gave up three runs and eight hits in six innings.