The Nationals took it to Brewers starter Matt Garza in the first inning.
Denard Span singled and Jayson Werth doubled. Following a walk to Adam LaRoche, Ryan Zimmerman provided a two-run single to give the Nationals a 2-0 lead.
After another Garza walk, this one to Bryce Harper, Ian Desmond's infield single scored LaRoche and the Nationals' advantage was 3-0.
Wilson Ramos then delivered a two-run single and the Nationals lead increased to 5-0.
Garza was lifted for former Nationals pitcher Marco Estrada. His only recorded out was a strikeout of Anthony Rendon. Previously this season, Garza's shortest outing was three innings in a loss at St. Louis on April 30.
Tanner Roark laid a bunt down that was fielded by Estrada, who threw to catcher Jonathan Lucroy to tag out Desmond at the plate. The play was reviewed by the crew chief. The ruling stood on the field because there was no violation of Rule 7.13, which deals with catchers blocking the plate.
Garza allowed five runs, all earned, in just one-third of an inning. He has now allowed 22 earned runs in 27 innings against the Nationals over six starts in his career.
Update: The Brewers notched a couple of base hits against Roark in the second to get on the board. Lucroy doubled with one out, stole third and came home on a Wilson Ramos throwing error, and the Nationals lead 5-1.
Update II: The Nationals got that run back in the third inning. Harper doubled and later scored on another Ramos single. Ramos now has two hits and three RBIs in the game. The Nationals lead 6-1.
Update III: The Nationals drew a pair of walks in the fourth inning off of Estrada. Zimmerman smacked a run-scoring single and the Nationals lead 7-1. Zimmerman has two hits and three RBIs.
Update IV: In the sixth, Rendon singled and Werth doubled. LaRoche brought Rendon home on a sac fly to left field and the Nationals lead 8-1.
Update V: Roark is done after a terrific outing. The right-hander allowed one run on six hits and a walk. He struck out five and finished with 112 pitches, 76 for strikes.
Roark has now allowed one run in 14 innings over his last two starts, lowering his season ERA to 2.91.
Left-hander Jerry Blevins came out of the bullpen to start the eighth. After inducing a groundout to open the inning, he surrendered a single to pinch-hitter Martin Maldonado and a two-run homer to Ryan Braun.
The Nationals still lead 8-3.
Update VI: The Nats are back in a first-place tie with the Braves after topping Milwaukee 8-3 and seeing the Phillies edge Atlanta 2-1.
Roark earned the win to improve to 9-6 on the season. Garza took the loss with his one-third of an inning, falling to 6-7.
Zimmerman and Ramos each drove in three runs to lead the offense as the Nats put themselves in position to win the series with a victory Sunday. Washington has won three of four and is now 52-43 on the season.