WASHINGTON (AP) -- Washington Nationals rookie pitcher Tanner Roark wanted to keep going.
He had thrown 101 pitches -- 23 more than he'd ever thrown in a single game -- but still wasn't ready to call it a night.
"I said, 'Nice game.' He said, 'You sure I'm through?'" Nationals manager Davey Johnson said as he began to smile. "I said, 'Yeah, you're through."
Roark was through, but Washington certainly isn't.
The right-hander threw seven shutout innings, and the Nationals beat the Atlanta Braves 4-0 to sweep a day-night doubleheader Tuesday, ensuring the Braves leave Washington without the NL East title.
The Nationals entered the nightcap, which followed their 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. Washington, which has won 10 of 11, has 11 games remaining.
Roark (7-0) allowed just two hits, struck out six and retired the final 13 batters he faced. Johnson even seemed to make up a word -- "posure," apparently a cross between poise and composure -- to describe Roarke.
"It's not smoke and mirrors right now," first baseman Adam LaRoche said. "When you get guys coming down to first talking about how good his stuff is, some really good hitters that are praising him, it says a lot."
After being called up in August, Roark was making just his third start.
"I'm just trying to do the same thing as I was doing all year and not trying to change anything," Roark said. "Keep the same mentality, a bulldog mentality, not giving in to anybody in any sense."
Roarke and the Nationals got cushion in the eighth inning, when Ryan Zimmerman hit a home run, Ian Desmond hit an RBI double and Adam LaRoche hit an RBI single. Steve Lomardozzi had a second-inning RBI single off Freddy Garcia (1-2).
Denard 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.
The Braves have lost nine of 13, but they still lead the division by eight games over Washington despite the sweep.
"We need to start playing a little better baseball and start swinging the bats," Atlanta manager Fredi Gonzalez said. "I like where we are, our position, but there's still baseball games to be played, and we've just got to get back on a roll again."
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 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.
In the ninth, 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.
NOTES: RHP Stephen Strasburg's bullpen session Monday went "great," 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.
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