The ball headed out toward the left-center field gap, the end to a near-perfect day, a knife in the back of Washington baseball history. Jordan Zimmermann rolled his neck and looked to the sky, stepped off the pitcher’s mound and put his hands on his hips. “Double,” Zimmermann thought. “No-doubt double.” The Nationals Park crowd, frenzied when Zimmermann had released his 104th pitch of Sunday afternoon, went still and quiet.

Moments earlier, at the start of the ninth inning, Steven Souza Jr. had emerged from the dugout for the first time all day and jumped in the air, bringing knees to chest. “Put yourself in the moment,” he thought. Now, the rookie call-up turned and sprinted for the last out. He dove, flying in the air, and snared the ball. He lifted his glove. Zimmermann thrust both arms into the air. The 35,085 people in the seats mimicked him. History had been saved.

On Sunday afternoon, the final day of the regular season, Zimmermann threw the first no-hitter in Washington Nationals history in a 1-0 victory over the Miami Marlins. The first no-hitter by a Washington major league pitcher since Bobby Burke no-hit the Boston Red Sox on Aug. 8, 1931, at Griffith Stadium came five days before the 96-win Nationals will start the playoffs as the top seed in the National League.

“It’s the perfect baseball day,” Manager Matt Williams said. “Eighty degrees and sunshine and the last day of the season. Lots of moves and some tense moments when it finally came down to it. So all in all, that’s probably the perfect baseball day.”

Opposing Marlins right-hander Henderson Alvarez — who threw a no-hitter on the final day of the 2013 regular season — Zimmermann needed only 104 pitches. He threw just 25 balls, walked one (Justin Bour in the fifth inning), struck out 10 and allowed only five balls to leave the infield — including the last out of the game, the screamer off the bat of Marlins leadoff batter Christian Yelich, a .285 hitter entering the day.

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)

“Even when I first got called up, I thought there was no way this would ever happen,” Zimmermann said. “My career numbers are something like one hit per inning, so I figure if I can make it out of the first, the hit’s coming in the second. But today was one of those special days.”

It came seven days after his last start, in Miami against the Marlins, when a line drive bruised his right shoulder. Williams planned to pull Zimmermann after five or six innings to preserve him for the playoffs. In the third inning, pitching coach Steve McCatty asked Williams what they would do if he reached the sixth inning without allowing a hit. “That’s not funny,” Williams replied.

Zimmermann reached the apex of a career that began in Auburndale, a map-dot farming town in Wisconsin with a population of 738, not all of whom were necessarily watching Zimmermann record the last out. “Are the Packers still playing?” Zimmermann said, smiling. “Everyone’s probably watching those guys.”

Zimmermann’s wife of nearly two years, Mandy, watched from the stands with Riley, his 10-month-old son. “But he might be down in the family room not knowing what’s going on,” Zimmermann said.

Game 162 had already become a procession of appreciation. Fans sang “Happy Birthday” to Ryan Zimmerman as he took the first at-bat of his 30s in the first inning. Denard Span tipped his helmet to the roaring crowd as he walked into the dugout after he set a new team record for hits in a season.

Ian Desmond’s solo homer brought another ovation. Roars came when regulars requiring rest for the postseason exited for pinch hitters — the Nationals used 16 players behind Zimmermann.

The loudest cheers came in the ninth, when Zimmermann walked to the mound, all zeroes on the scoreboard.

“I was just trying to keep it all in,” Zimmermann said. “I knew I was getting close. Obviously with the fans going crazy, you can definitely notice you’re getting close to the end.”

For the first out in the ninth, Adeiny Hechavarria grounded to Jeff Kobernus at second base. Pinch hitter Jarrod Saltalamacchia drove a flyout to deep center, and rookie Michael A. Taylor gloved it a few feet in front of the warning track. One out to go.

“I just try to be myself,” Zimmermann said. “The adrenaline starts pumping, and some of the balls are up in the zone. I was getting pretty amped up. But I tried to tell myself to calm down and keep the ball down.”

In left field, Souza played Yelich a step closer to the line on account of the lefty’s opposite-field swing. Souza told himself to dive, run into a wall, break an ankle — whatever he needed to do to make a catch.

“The more you grasp the reality of the moment,” Souza said, “the more you can be ready for anything that comes at you.”

Zimmermann rifled Yelich a 2-1, 94-mph fastball. It stayed belt high and over the center of the plate. Yelich smoked it. Souza turned and sprinted.

“I didn’t think there was any way,” Nationals closer Drew Storen said. “There’s just no way he’s going to stay under control.”

Souza had never dived backward, leaving himself horizontal to the ground, in his baseball career. “I’ve actually always wanted to do that,” he said. “I didn’t think that would be the time I would practice it.”

“It was almost like it was in slow motion, watching him leave the ground,” Taylor said later.

Souza flopped to the turf. The ball disappeared underneath him. Zimmermann knew Souza had caught it when he lifted his black glove in the air. The park erupted. Teammates mobbed Zimmermann first, then moved to Souza, then formed one giant pile around shortstop.

Souza’s parents had flown from Seattle to watch him receive the Nationals’ minor league player of the year award in a pregame ceremony Thursday, and they stayed through the weekend. They sat in Section 119, behind the plate on the third base side, and watched the scene unfold.

“Heart-attack view,” Steven Souza Sr. said. “To see my son just keep that no-hitter there, it was just amazing. Amazing joy.”

Afterward, teammates doused Zimmermann with water and smeared his face with whipped cream. Zimmermann walked through the Nationals’ clubhouse, hair tousled and ice wrapped around his right shoulder. He hugged Souza.

“Whatever he wants he can have,” Zimmermann said. “I’ll buy him anything.”

“I’ll be looking for a Beemer in my garage,” Souza said. “No, I’m not looking for anything at all. Just to make that catch is enough for me.”

Teammates shared videos of Souza’s catch on their phones and relived the day. Fans who had won a raffle lined up to receive jerseys off players’ back — including one who took home Zimmermann’s.

“If somebody wrote that as an ending to the season,” Storen said, “I don’t think anybody would believe it.”

Only it’s not the end. On Friday, the Nationals will begin the National League Division Series at Nationals Park against the winner of Wednesday’s wild-card game between the San Francisco Giants and Pittsburgh Pirates. The first no-hitter and the best defensive play since baseball returned to Washington were behind them. So much, they hoped, was ahead.

“You just hope you can keep this thing moving,” third baseman Kevin Frandsen said. “Our fans earned that as well. They were in it the whole time. I just can’t wait for Friday.”