Tanner Roark threw seven shutout innings, and the Washington Nationals beat the Atlanta Braves 4-0 to sweep a day-night doubleheader Tuesday, ensuring the Braves leave Washington without the NL East title.
Roark (7-0) allowed just two hits, struck out six and retired the final 13 batters he faced.
Ryan Zimmerman hit a home run, Ian Desmond hit an RBI double and Adam LaRoche hit an RBI single in the eighth inning. Steve Lomardozzi had a second-inning RBI single off Freddy Garcia (1-2).
Washington entered the nightcap, which followed the Nationals' 6-5 win in the makeup of a series opener postponed by a shooting rampage a day earlier at the nearby Navy Yard, within 4½ games of Cincinnati for the NL's second wild-card berth. The Nationals, who have won 10 of 11, have 11 games remaining.
The Braves have lost nine of 13, but they still lead the division by eight games over Washington despite the sweep.
Craig Kimbrel had converted 37 consecutive save chances since early May, and Andrelton Simmons began the day with the second-best fielding percentage among National League shortstops. But they conspired to blow a three-run lead in the ninth inning of the first game.
Simmons allowed Denard Span's grounder off Kimbrel to bounce through his legs as two runs scored on the game-ending play.
Pinch-hitter Chad Tracy had an RBI grounder against Kimbrel as Washington kept Atlanta's magic number at four for clinching the NL East for the first time since the Braves' streak of 11 consecutive division titles from 1995-05. A sweep of the day-night doubleheader would have sealed the division for Atlanta.
Kimbrel (3-3), who leads the major leagues with 47 saves, blew a save chance for just the fourth time this season.
Atlanta trailed 3-0 but took a 4-3 lead in the eighth on Gattis' two-run homer off Tyler Clippard on an 0-2 pitch, which stopped an 0-for-18 skid. The Braves added a run in the ninth when Elliot Johnson singled, advanced on a throwing error by left fielder Bryce Harper, stole third and came around as Desmond allowed Freddie Freeman's four-hop grounder to shortstop to bounce off the heel of his glove for his 18th error this season.
In the ninth, Adam LaRoche walked on a full count, Wilson Ramos reached on an infield single and Anthony Rendon walked on a 3-2 pitch. After Tracy's grounder, Atlanta elected to pitch to Span with first base open, and he hit a three-hopper over the mound that rolled past Simmons into center field. Span was given an RBI, with the second run scoring on the error.
Ian Krol (2-1) faced two batters in the ninth, giving Washington its first win in seven home games against Atlanta this year.
Before the games, both teams stood in front of their dugouts, heads bowed, and a color guard was stationed behind home plate during a minute of silence to pay tribute to the people killed Monday and those affected by the shootings.
In the second game, Span's fifth-inning single extended his hitting streak to 28 games, breaking a tie with Colorado's Michael Cuddyer for the longest in the major leagues the last two seasons..
NOTES: RHP Stephen Strasburg's bullpen session Monday went "great," Nationals manager Davey Johnson said. Strasburg is set to start Thursday against Miami after missing Friday's turn due forearm tightness in his pitching arm. ... Adm. James Winnefeld, the vice chairman of the Joint Chiefs of Staff, greeted players in the Nationals clubhouse before the game, handing out blue and gold Navy caps to wear during warmups. . Freeman became the first Atlanta player with 100 RBIs in a season since Chipper Jones and Jeff Francoeur in 2007.