Tim Redding won his first start in almost three years. He went six innings, allowed two runs and five hits, walked one and struck out one.
The Nationals won a second consecutive game for the first time since taking three in a row from June 12th through the 14th.
They sent eleven batters to the plate in the sixth to erase a 2-to-1 deficit.
Felipe Lopez homered and reached base four times for Washington.
The division-leading Brewers have lost five of six, and failed to hit a home run for the first time in 17 games. The closest Milwaukee came to connecting was when Gabe Gross backed center fielder Nook Logan to the wall leading off the fifth.