ATLANTA — Washington slugger Bryce Harper owns Atlanta pitcher Julio Teheran and the same could be said about the Nationals against the Braves.

Harper smashed a grand slam in the second inning after a bases-empty homer in the first off Teheran and finished 4-for-4 overall with an intentional walk as the Nationals won 14-4 on Wednesday night for their 31st victory in the past 40 games against Atlanta.

Harper, who is batting .404 this season with six homers and 18 RBIs, has driven in 17 runs in his career against Teheran while going 15-for-33 against the right-hander.

Joe Ross, recalled from Triple-A Syracuse, got plenty of support from Harper and Ryan Zimmerman in a 20-hit Nationals outburst and went seven innings to win his season debut.

Ross (1-0) retired 14 of the last 15 batters he faced. The right-hander allowed six hits and three runs while striking out seven and walking one.

Zimmerman made it a rout with a grand slam off reliever Ian Krol in a five-run eighth. It was the first time the Nationals hit two slams in a game since Josh Willingham did it himself in 2009 at Milwaukee.

Freddie Freeman hit his sixth homer of the season in the third inning to set the Atlanta record of reaching base safely in 12 consecutive plate appearances.

Freeman, who had walked his first time up, grounded out in the sixth to end the streak before delivering an RBI single in the eighth.

Teheran (1-1) came in with a 0.95 ERA for his first three starts, but allowed seven runs in four innings against the Nationals.

Harper picked on a first-pitch fastball down the middle of the plate for his first-inning homer to right-center field, then deposited a hanging 1-0 slider from Teheran over the center-field fence in Washington’s five-run second that erased a 2-1 Braves lead.

Adam Eaton, who has reached base safely in all 11 games he has started for the Nationals, had an RBI single to tie the score before Harper connected for the grand slam.

Nick Markakis and Brandon Phillips had RBIs singles in the first inning and Freeman, who had scored after a walk earlier, homered over the center-field fence off Ross on a 1-0 fastball in the third.

The Nationals got that run back in the fourth, though, as Teheran added to his rough outing with a run-score wild pitch.

NOTES: It took RHP Blake Treinen, who had a 7.11 ERA in eight games, less than three weeks to lose his closer’s role with the Nationals. Manager Dusty Baker said RHP Shawn Kelley and RHP Koda Glover would share the ninth inning, with Treinen returning to a setup role. … Washington LF Jayson Werth left the game during a third-inning at-bat when he hurt himself checking a swing. … The Nationals placed LHP Sammy Solis on the 10-day disabled list with elbow inflammation to make room for RHP Joe Ross, who was recalled from Triple-A Syracuse to start against the Braves. … Atlanta LF Matt Kemp (hamstring) played a rehab game for Triple-A Gwinnett on Wednesday and is expected to return from the disabled list for the series finale against the Nationals on Thursday. … Washington SS Trae Turner (hamstring) played in an extended spring training game and will be activated during the weekend series in New York against the Mets. … RHP Stephen Strasburg (1-0, 3.00 ERA) will pitch on Thursday for the Nationals, with RHP R.A. Dickey (1-1, 3.86) starting for the Braves.