Winning pitcher Tomo Ohka, who was traded by the Nationals to Milwaukee earlier this season, raised his record to 6-4. Ohka, traded after on-field confrontation with Washington Manager Frank Robinson, surrendered three runs and four hits in seven innings with no walks and six strikeouts.
The Brewers have won five of six on the heels of a three-game skid.
Milwaukee closer Derrick Turnbow earned his 19th save.
Losing pitcher Ryan Drese dropped to 3-2. In three innings, he yielded five runs and five hits with one walk and no strikeouts.
Brian Schneider had two hits and two RBI for Washington, which has dropped five of six and seven of its last nine.