Jayson Werth stood in the corner of the Washington Nationals’ clubhouse Tuesday night, sipping a Bard’s ale and posing for cellphone pictures, bursts of champagne suds flying past. Bryce Harper floated through the room with a DCFD fireman’s helmet on his head, a gift from the department shipped to Turner Field the day before, emblazoned with “Harper 34.” Crushed Miller Lite cans and corks littered the floor. Someone yelled, “Let’s go outside!”

The players trickled out, down a hallway and into the visitors dugout at Turner Field, where fans still filled seats. Of all the days for the Atlanta Braves to schedule a country music concert. With their 3-0 victory over the Braves, the Nationals clinched their second National League East title in three seasons, snatching the crown off the collective heads of their hosts.

“I think it’s even a little sweeter,” Nationals principal owner Mark Lerner said. “I loved that team in ’12. But this team is a couple years more mature. I think they’re ready to take the next step. We got a ways to go yet.”

The Nationals completed a 58-day blitz in which they turned a tie for the division lead into a runaway. Their 87th victory, in Game 150, pushed them 121 / 2 games ahead of spiraling Atlanta with 12 games to play. On Oct. 3, the Nationals will play their first playoff game since Game 5 of the 2012 National League Division Series, a punishing loss they never had the chance to redeem in 2013, a slice of heartbreak they can atone for now, as a better version of themselves.

“We know we have worked enough to deserve this,” reliever Craig Stammen said. “I don’t know in 2012 if we really figured out what was going on. Things went so smoothly that it was like, ‘Yeah, we’re here.’ The last couple years, we put in the work to get to this point. For us, this isn’t good enough. We’ve got bigger goals in mind. That’s probably the difference. We’re not satisfied.”

Nationals players celebrate their second National League East title in three years after a 3-0 victory over the Atlanta Braves on Tuesday. (The Washington Post)

The Nationals weathered injuries to two-fifths of their starting rotation — Doug Fister, remember, spent opening day on the disabled list — and two-thirds of their starting lineup — Wilson Ramos broke his hamate bone in the seventh inning of the season. The Nationals played 18 games all season with the starting lineup they envisioned. They went 11-15 in May. First-year Manager Matt Williams moved Ryan Zimmerman, their franchise third baseman, to left field. When they shifted Zimmerman back to third, Harper publicly requested Zimmerman stay so he could play center field — the position that happened to belong to Denard Span.

“There were more sleepless nights than I ever imagined,” Williams said.

“We are so proud of this organization,” Nationals managing principal owner Ted Lerner said in an e-mailed statement. “Watching them clinch their second NL East division championship in three years means so much to our fans, our city and our family. Mike Rizzo and Matt Williams should be commended for building and leading a championship club. Tonight, we celebrate this milestone but realize that there is still work to do and goals to accomplish. We are looking forward to the possibilities that lie ahead.”

They handed the ball Tuesday night to Tanner Roark, the 27-year-old right-hander who had been acquired at the trade deadline in 2010 for Cristian Guzman — a shortstop then 15 games from the end of his career. Roark toiled in the minors for years. He sprang forth from their minor league system last fall and never woke up.

“Nerves were higher than ever,” Roark said. “I get nervous before every game, but especially tonight. If you’re not nervous, you’re not normal.”

Roark’s ascension reached a new apex Tuesday night, when he fired seven scoreless innings, held the Braves to five hits, struck out four, walked none and threw only 89 pitches. In February, he came to Viera, Fla., to compete for a roster spot. Tuesday night, he surpassed 190 innings and lowered his ERA to 2.85. That is how division titles are won.

“I don’t try to think about it,” Roark said. “It’s been a long road. It’s been an amazing road. Now, we’re NL East champs. It’s something I never fathomed.”

The Post Sports Live crew makes a case for Nationals manager Matt Williams to win manager of the year for the National League after leading the team back to the playoffs. (Post Sports Live/The Washington Post)

The Nationals’ first runs came in the sixth inning. Werth stood on first base after a walk. Aaron Harang, the burly right-hander who had shut down the Nationals all year, fired Ian Desmond a 2-2 breaking ball. Desmond obliterated the pitch, sending it soaring through the soupy Atlanta air. The ball landed about 20 rows over the left field fence and bounded off a suite window. Holding to the tradition reserve Kevin Frandsen began in August, the Nationals tossed Desmond’s helmet around the dugout like a basketball. It returned to him, and he reverse-dunked it through the hoop a teammate formed with his arms.

Once Desmond homered, clubhouse attendants covered lockers with plastic sheets. Roark completed the sixth inning, then a seventh. Roark usually heads into the clubhouse after starts for treatment. Now, he watched from the dugout and his heart fluttered.

Tyler Clippard, an all-star this season, the rare set-up reliever who becomes part of the franchise bedrock, pitched a scoreless eighth inning. Storen, the closer who blew the Game 5 save, got demoted and then reclaimed the ninth inning, jogged in from the bullpen, pants pulled high to reveal bright-red socks. Seven pitches, seven strikes and three groundballs later, the Nationals clinched.

“There’s nobody else that deserves to close out that game [in] the eighth and the ninth inning,” rookie reliever Aaron Barrett said. “It’s meant to be, you know? Especially to close it out here? I told those guys, ‘That’s the way the baseball gods work sometimes’ ”

Storen watched the last groundball roll into Asdrubal Cabrera’s glove. Storen slapped his glove twice and waited for onrushing teammates — reserves from the dugout, relievers from the bullpen, outfielders in shallow center leaping and bumping chests.

They formed into a jumping, screaming pile in the infield. One of them chucked a black glove into the air. The sparse crowed hurled wan boos. They rushed to grab gray T-shirts proclaiming them champions, Desmond leading the way. Mark Lerner hugged Roark. Fister hugged Rizzo. Everybody hugged everybody.

“We took a step back last year, but it’s good to be back on top of the division,” Werth said. “These guys, they fought hard all year. We came into spring training ready. We had a job to do. Six months later, here we are. We did it.”

They tore through the bottles — eight cases of Korbel, one of Dom Perignon, 25 cases of Miller Lite. The party spilled out to the field. Players stood in front of their bench and watched country singer Cole Swindell. Scott Hairston danced on the warning track with his two sons. Ross Detwiler and Stammen leaned against the dugout railing and guzzled Bud Lights. They laughed as the laser lights illuminated their faces, soaked and too happy to care how they would feel in the morning.

In the corner, Stephen Strasburg’s daughter, the baby girl who hadn’t been born in 2012, sat on his shoulders. Strasburg rocked to the music as he peeked at his wife, whose initials — R.E.S. — he wears on his spikes, and smiled ear-to-ear. Strasburg dropped his daughter to eye level and kissed her on the cheek.

“We have grown up,” Stammen said.

Not long after, all around Strasburg, teammates swayed and sang along. They belted out the lyric: “The heart don’t forget something like that.”