WASHINGTON — When Ryan Zimmerman, the Washington Nationals first baseman, was a young boy playing baseball in his backyard, he often imagined that he was in the World Series.

Two outs. Bottom of the ninth. Victory just one play away. It was high drama and his team — he recalled that it was either the Baltimore Orioles or the Atlanta Braves — won every time.

“No matter the scenario,” he said with a laugh. “It always had that perfect ending.”

Zimmerman, 35 and a veteran who has been with the Nationals since the team arrived in Washington in 2005, has been waiting 14 years for that perfect ending here. Considering the team began this season with a 19-31 record, it didn’t seem like this would be their year.

But Mark Lerner, the Nationals’ principal managing owner, called it “some kind of magic” as the team turned its horrendous start into a fairy tale that’s near its end. The team won a nail-biter wild-card game. It beat the Los Angeles Dodgers in a Game 5 eliminator to win its first division championship, the first time in four previous tries that it succeeded.

And on Tuesday night, in front of a crowd of 43,976 believers, the Nationals completed a four-games-to-none sweep of the St. Louis Cardinals in the National League Championship Series. Just one season after Bryce Harper, their franchise player, left for a division rival, the team is headed to its first World Series.

Zimmerman’s long-imagined perfect ending could actually become reality. The whole city seems eager about the potential happy ending.

On Tuesday morning, radio DJs played songs like Kool and the Gang’s “Celebration” in honor of the Nationals making it to the World Series, even though the decisive fourth game against the Cardinals had yet to be played.

A string of (Max) Scherzers, (Anthony) Rendons and Zimmermans headed into schools across the city as students wore team jerseys to show their Nationals pride.

Fans arrived at bars and restaurants around Nationals Park more than five hours before the game, conspicuously leaving work early for the moment the team would bring the World Series back to Washington for the first time in 86 years.

“In Washington, we kind of got used to heartbreak,” said Trish Gilbert, who, with her husband, John, has been a season ticket holder for nearly a decade. “But then came the Capitals, and then what about the Mystics? Things are changing.”

The Washington Capitals won the Stanley Cup in 2018 after years of failing to live up to their potential. And last weekend, the Washington Mystics won the WNBA championship. The Mystics’ star player, Elena Delle Donne, threw out the first pitch for Tuesday’s game to loud cheers.

Nationals manager Dave Martinez said his team was inspired by those victories and that he “wanted to be a part of that, too.”

“I said, this going to happen,” he said, describing what he had told his players. “It’s going to happen in our world, in the baseball world. It is. We’ve just got to believe.”

Ask the Nationals exactly how they rebounded from their dismal start, when some players had heard that Martinez might be fired and the whole team would be traded, and they will give you dozens of answers.

It’s the pitching, they said. With Stephen Strasburg, Max Scherzer, Anibal Sanchez and Patrick Corbin, they have a stinging rotation with some of baseball’s best arms.

It’s Martinez, they said. He brought a needed even-keeled attitude to the team and helped foster relationships between the young players and veterans.

Sanchez said from the first moment Parra stepped into the dugout in May, he began injecting positivity into the clubhouse. A day after he arrived, he hit a grand slam against the Dodgers in a 5-2 victory. It was a good combination.

From that moment on, the team has gone out of its way to have fun instead of just playing hard and being so serious, Sanchez said.

Players started dancing in the dugout. Parra began blaring his upbeat music in the clubhouse and injected an infectious positive energy that drew in other players. Martinez noticed that the team was looser. Subsequently, it started playing better.

Strasburg, who is known to be reserved, even began to dance.

“Have you ever seen Stephen Strasburg dance?” Martinez said. “It will make you laugh, make you have fun. I’m not saying he’s bad. He’s actually getting a lot better.”

Martinez described one point in the season when Parra was batting 2-for-30 and was upset about it. Martinez called him into his office to remind him that his role on the team was to “bring the energy” and “play that music, get loud and have fun,” no matter what his batting percentage is.

Parra took his advice — and his batting improved.

On Tuesday, the fans at the ballpark were ready and waiting for Parra, who came in as a pinch-hitter late in the game. He has rallied thousands of people with his personality.

Some fans were dressed up in full head-to-toe shark outfits. Others had rubber shark heads glued to their Nationals caps. When his Baby Shark music began to play, the entire crowd started clapping its hands together to mimic a shark bite. When Parra hit a single, even Cardinals first baseman Paul Goldschmidt seemed to laugh with Parra about the Baby Shark phenomenon.

After the game, he was the life of the party. In the clubhouse turned frat house, amid showers of Champagne and beer, Parra grabbed Strasburg and danced the merengue to a vibrating beat.

Before Zimmerman entered the fray, he walked toward the dugout and stood in front of a throng of fans in the stands. Lerner had given him the championship trophy right away, wanting Zimmerman to be the first player to touch it because “he deserves it.”

“You won’t find a player with his kind of loyalty,” Lerner said. “He’s absolutely amazing and we wouldn’t be here without him.”

But the fans seemed to know that already. Zimmerman lifted the trophy before them, closed his eyes and shouted, “Yeah!” And just like he imagined as a boy, the crowd roared for him.