WASHINGTON -- Bryce Harper smashed a grand slam for his 100th career homer, Wilson Ramos had a homer and two RBIs and Stephen Strasburg allowed just two runs as the Washington Nationals beat the winless Atlanta Braves 6-2 on Thursday to complete a four-game sweep.

Harper, the reigning National League MVP, crushed a 1-0 pitch from Braves starter Julio Teheran (0-2) off the second deck in right field with two outs in the third inning. At 23 years and 181 days, Harper became the eighth-youngest player to reach 100 homers, just 20 days shy of Johnny Bench and four days ahead of Albert Pujols.

Harper's third homer of the year gave the Nationals a 4-1 lead and led to a short curtain call from the dugout in the last game of the homestand. It was the first career grand slam for Harper, who hit 42 homers last season.

The Braves are 0-9 this season and have lost their last 14 games at Nationals Park. Washington (7-1) is 27-9 against Atlanta since June 21, 2014.

Ramos hit a solo homer in the fourth to give Washington a 5-1 advantage and his RBI double in the sixth made it 6-1. His double drove in hot-hitting Daniel Murphy, who had doubled.

The Braves assumed a 1-0 lead in the third on a RBI single by Nick Markakis off starter Stephen Strasburg (2-0), who gave up four singles and two runs in 7 2/3 innings with seven strikeouts.

Markakis had his second hit, an RBI double, in the eighth off left-handed reliever Felipe Rivero to cut the margin to 6-2.

Teheran allowed six runs and six hits in seven innings and fell to 3-3 in 13 career starts against Washington. Strasburg was originally slated to pitch Wednesday, but his start was pushed back a day because of illness.

Washington has won five in a row overall and seven straight dating to last season against the Braves, who have been outscored 55-23 this season.

The Braves have allowed 13 homers this season and hit only three. The Nationals have gone deep eight times while giving up just three homers.

NOTES: The Braves entered the game ranked next-to-last in many offensive categories in the National League, including hitting (.199), runs (22), total bases (71) and homers (three). ... Atlanta 1B Freddie Freeman got the day off Thursday as he entered play hitting .080 in 25 at-bats with nine strikeouts. ... Washington 2B Daniel Murphy reached base in 17 of his first 28 plate appearances and was second in the league in hitting at .500 through Wednesday. ... The Braves start a series in Miami on Friday with Atlanta RHP Williams Perez (0-0, 7.71) slated to face Marlins LHP Wei-Yin Chen (0-0, 9.00). ... The Nationals' 6-1 start was the best beginning to a season in D.C. baseball history since the 1951 Senators, who also began 6-1. ... Nationals manager Dusty Baker was drafted in the 26th round in 1967 by the Braves and played eight seasons in Atlanta.