Stephen Strasburg pitched into the eighth, Bryce Harper hit a grand slam, and Washington completed a four-game sweep of Atlanta, 6-2, on Thursday.
Strasburg (2-0, 1.98 ERA) gave up two runs on four hits in seven and two-thirds innings, striking out seven and walking two.
Harper hit the grand slam, his third homer of the season, and 100th of his career, with two outs in the third.
Wilson Ramos had a pair of RBI hits on a 2-for-3 day at the plate.
The Nationals improve to 7-1 on the season; the Braves fall to 0-9.