Harper clubbed the first pitch he saw from Braves starter Sean Newcomb in the second inning over the wall in straightaway center. It was Harper's third home run of the season and the 20th of his career against Braves pitching. He also drew four walks and scored three runs.

Tanner Roark allowed one run in seven innings for the win, giving the Nationals their first 4-0 start to a season in franchise history.

Washington already has nine home runs and has yet to trail in a game.

Newcomb got off to a rocky start for Atlanta and surrendered six runs, five earned, before exiting in the fifth inning.

Atlanta committed two errors in the first inning, one a misplayed grounder by first baseman Freddie Freeman and the second a throwing error on a pick-off attempt by Newcomb. The Nationals capitalized with an RBI groundout from Anthony Rendon that scored leadoff man Trea Turner. Howie Kendrick followed with a double off the right-field wall that scored Harper to make it 2-0.

The Nationals have scored in the first inning in each of their four games this season.

Freeman drove home Ender Inciarte with an RBI single in the fourth inning for the Braves' only run.

Brian Goodwin tacked on a two-run single in the ninth, and Pedro Severino had two hits and an RBI and scored two runs for Washington.

The Nationals won 97 games last season but came up short in a seven-game playoff series with the Cubs. They're considered the clear-cut favorite in the National League East and are off to an impressive start to the season.

Atlanta lost 90 games last season and remains in rebuilding mode. They'll try to bounce back in the second game of the series on Tuesday.

A.J. Cole gets the start for the Nationals against the Braves' Julio Teheran.

--Field Level Media