Brandon Phillips added a two-run clout for the National League Central-leading Reds, who clinched their three-game series.
Bronson Arroyo (5-6) earned the victory, stifling the Brewers on two runs over six full innings. The Reds right-hander struck out six, surrendered five hits and walked two.
Milwaukee starter Yovani Gallardo (8-7) was touched for four runs on nine hits over 5 2/3 frames.
Corey Hart managed the Brewers' only RBI.