Adam LaRoche hits the winning home run in the 15th inning against the Braves. The game lasted 5 hours 29 minutes. (Scott Cunningham/Getty Images)

At 12:49 a.m. Sunday morning, Saturday night’s dramatic and exhausting slugfest with the Atlanta Braves lasting into the following day, Dan Haren fired the game’s 518th pitch. He struck out Jordan Schafer on a splitter and high-fived catcher Wilson Ramos, who crouched behind the plate for all 15 innings. Haren sealed the Washington Nationals8-7 win, the longest game in team history, with his first-ever save. He was one of 18 pitchers to appear in the game, along with 26 position players.

It felt like more than five and a half hours, however, had passed since the game began with drama. The Nationals and Braves took the field at 7:20 p.m. and by the end of the second inning neither starting pitcher was still in it. The frustration that had been brewing between these two teams finally erupted in the opening frame in the form of a Stephen Strasburg fastball to Justin Upton’s thigh. Then, it devolved into hours of wildness, misery and ultimately exhilaration.

“Golly, what a battle,” first baseman Adam LaRoche said.

Strasburg wouldn’t complete another inning, tossed for the first time in his career after he fired three straight wild pitches in a strange sequence in the second inning.

Manager Davey Johnson also was ejected. Left fielder Scott Hairston joined them after arguing a called third strike late in the game, forcing this ongoing saga’s central figure, bruised Bryce Harper, into action. With two outs in the ninth, closer Rafael Soriano blew his second straight save.

The entire bullpen was used. Tuesday’s starter, Haren, volunteered for duty. Defensive replacement LaRoche provided the deciding home run.

The game had several standout performances: four dominant innings by rookie long reliever Tanner Roark in relief of Strasburg, two bounce-back innings from rookie Ian Krol, three late powerhouse innings from Craig Stammen, Haren’s save and LaRoche’s homer. But the contest served as the venue for baseball players to settle old scores. An early bullpen implosion. A blown save. Twenty-two runners left on base. Thirty-six strikeouts. And two teams with budding distaste for each other.

These disappointing Nationals have been kicked around by the Atlanta for over four months, their play against their fiercest division rival dismal at best. Harper took three pitches to the body by Braves pitchers in the past two weeks, one of the two he sustained on Friday night hard enough to force him to sit out the start of Saturday’s game with a bruised arm. That is what finally forced the Nationals to take action.

Upton, the Braves’ best hitter, was batting second. Strasburg allowed a leadoff home run to Jason Heyward but the Nationals led 2-1. Strasburg reared back and fired a 97-mile per hour fastball right at Upton’s left hip. Even without an explanation, a first-pitch fastball to the midsection of the other team’s best player is a fairly clear message. And given what had transpired recently, it perhaps didn’t need any words.

“I’m not gonna get into that,” Strasburg said.

After the ball plopped off his side, Upton took first base without any issue. Strasburg’ s face was blank. Home plate umpire Marvin Hudson warned both dugouts. The Turner Field crowd erupted and cheered “Freddie! Freddie!” as the next batter, Freddie Freeman, stepped in the box. Harper watched from the dugout.

No one, including Strasburg, would say if the plunking were intentional. But an obvious admission of motive almost didn’t matter.

“If [Strasburg] decided to do it on his own, I’m proud of him,” bench coach and acting manager Randy Knorr said. Added LaRoche: “Whether it got away from him or not, he’s got my respect. I was impressed.”

“You can say whatever it is, but the game will always police itself,” Stammen added. “And credit to their hitters, when they got hit, they walked down to first base, they took it like men and that’s kinda how it is and it should be over now.”

With his first few pitches in the bottom of the second, Strasburg’s command was off. He walked the first batter, Schafer, on four pitches. Facing Andrelton Simmons, he fired a wild pitch low and outside that allowed Schafer to take second base. Pitching coach Steve McCatty paid a mound visit.

Strasburg fired another wild pitch, this time behind right-handed Simmons and to the backstop. Ramos crouched down behind the plate again and set up inside. Strasburg uncorked yet another wild pitch, again behind Simmons and to the backstop. Schafer scored easily.

“I can’t really explain it,” Strasburg said. “Just didn’t really feel good out there and couldn’t hit the spot.”

As he stood near home plate, Strasburg’s face was blank. Hudson tossed him from the game. Strasburg said nothing and, with his head down, walked slowly off the field. Johnson ran out to talk with Hudson, but he, too, by rule was ejected because of the warning the inning before. Asked later if he understood why he had been tossed, Strasburg said: “Yeah, makes sense.”

And, of course, the baseball gods somehow found a way to get Harper into the game. With a 7-5 lead in the top of the ninth, Hairston struck out on a low 2-2 fastball from David Carpenter. Hairston appeared to say something to Hudson, who quickly tossed him. With Roger Bernadina and LaRoche already substituted into the game, Knorr sent him out to left field.

With a two-run lead in the ninth, the Nationals turned to their high-priced closer Soriano, coming off two bad outings. After a quick out, he nibbled around the strike zone and walked pinch hitter Gerald Laird on six pitches. It was the same cardinal sin that doomed his last appearance in which blew a save.

Soriano got next pinch hitter Evan Gattis to roll over on a cutter, but the groundball was deep in the hole. Desmond nabbed the ball but the relay throw from Anthony Rendon couldn’t beat a racing Gattis at first. Two pitches later, Heyward added to the Nationals’ season-long misery by mashing a high and outside fastball over the right field fence. It was Soriano’s sixth blown save of the season, tied for second in the NL.

After Soriano’s blunder, Krol tossed two crucial scoreless innings a night after serving up the game-winning home run to Upton. Stammen, the final National reliever in the bullpen, jogged out of the bullpen for the 12th inning at 11:39 p.m.

“I figured I’m going to pitch until the game’s over,” he said. “So, I’m either gonna get walked-off on, or I’m gonna win the game . . . You’re kinda like, ‘Let’s have fun and see what happens and whatever does, that’s the way it is.’”

The Nationals offense turned dormant after Zimmerman’s eighth inning home run, going 0 for 16. Zimmerman snapped the skid with a two-out single in the 13th inning off Tuesday’s scheduled starter, Kris Medlen. LaRoche would the decisive hit an inning later.

Haren threw a 30-pitch bullpen session earlier in the day and lifted his upper body. Once Strasburg was ejected, he volunteered his services. He could tell what direction the game was headed. He jogged out to the mound for the 15th inning for the first time in his career. LaRoche would have been the next option, the first position player to appear.

“Basically it was down to me,” Haren said. “The best part of it was [LaRoche] hitting the homer. Me coming in for a tie game on the road, who knows how long I would’ve been out there. But he hit the homer and it was like, ‘OK, just nail it down and that’s it.’ ”