The Cubs celebrate their 6-4 win over the Cardinals in Game 4 of the National League Division Series at Wrigley Field. (Jonathan Daniel/Getty Images)

The ball soared through the gentle autumn light, in the general direction of Lake Michigan, propelled by another ferocious swing from another fearless and unbearably young Chicago Cub. Kyle Schwarber dropped his bat where it lay and watched the baseball hang in the air. It disappeared behind the right field scoreboard, out beyond the bleachers, and landed on Sheffield Avenue. Schwarber’s blast had done what no one inside the biggest party in town would have dreamed, even long past the final out. It had left Wrigley Field.

The St. Louis Cardinals would not depart meekly into winter, pushing the Cubs with their depleted roster until Game 4 of the National League Division Series became a classic. What chance did they have, though, against the will of 42,411 partygoers and the power of the Cubs’ precocious lineup? The Cubs’ 6-4 victory over the Cardinals thrust them into the National League Championship Series and touched off a celebration Wrigley had not seen in its first 101 years.

Until Tuesday evening, the ballpark on Clark and Addison had never hosted the clincher of a playoff series the Cubs won. It happened at 6:56 p.m. local time, when closer Hector Rondon struck out Stephen Piscotty. Players streaked toward the middle of the diamond, flinging gloves into the air. Kris Bryant and Anthony Rizzo met at the mound and embraced. In the bleachers they flew ‘W’ flags and hugged and sang, “Go Cubs Go.”

“I had to pinch myself,” Cubs President Theo Epstein said. “It’s not enough watching guys who were in instructional league last year hitting bombs over the scoreboard in the NLDS. It had to be the first time we played the friggin’ Cardinals in the playoffs. To win three in a row against those guys, who we have the utmost respect for, it’s incredible.”

The Cubs took the NL Division Series how Epstein envisioned they would win someday: with more raw power than any other team can match. It just happened sooner than expected. Javier Baez, Rizzo and Schwarber — ages 22, 26 and 22 — mashed home runs. Baez gave the Cubs their first lead, Rizzo took it back and Schwarber provided insurance. Together, they gave the Cubs 10 home runs in the series’ four games.

“We’re a scary team to play,” Cubs ace Jake Arrieta said. “Nobody wants to play us right now.”

Epstein also constructed the 2004 Boston Red Sox, who ended New England’s 86-year World Series drought. The Cubs’ dry spell stands at 107 years. The teams are vastly different in build, a cast of hardened veterans compared to a collection of kids. What they share is an audacious spirit — “Swagger,” General Manager Jed Hoyer said — and a yearning fan base.

“It’s awesome what’s going on in the city,” said Manny Ramirez, a member of the 2004 Red Sox and now a Cubs coach. “It reminds me of when I was in Boston in ’04. You know that we broke the curse. It was crazy. And I think it’s going to happen here. We got such a good team.”

Epstein sees a deeper connection between the Red Sox who broke a curse and the Cubs who are trying to. By his nature, Epstein rejects lazy narratives. He would not deny an elemental trait, one that defies age or era, the teams share. Those Red Sox came together over the heartbreak of their 2003 season. These Cubs have bonded over minor league bus rides and learning life in the majors. They both created something that outside the masculine confines of a clubhouse might be referred to as love.

“There’s a real joy to what they’re doing,” Epstein said, standing on Wrigley’s infield. “The biggest thing in ’04, I thought, we came back because the guys in that clubhouse cared more about the other 24 guys than they cared about their own interest. Not to get corny, but the human spirit: You can do more for other people than you can necessarily do for yourself. That’s how you overcome adversity. Maybe that’s how a real young team wins 97 games — 101 now. They really do care about each other. Don’t underestimate how much that matters.

The bleachers did not completely empty until two hours after the last out. Before players spilled onto the field and stood on dugouts, they doused each other in Budweiser and Canard-Duchene. In one corner, Pearl Jam lead singer Eddie Vedder, Epstein’s buddy, took in the flashing lights and champagne spray wearing a backward Cubs catcher’s helmet. Rizzo and catcher David Ross shouted at each other what has become their motto, directed at doubting opponents: “We’ll see!”

The Cubs have shown them all. Their youth has served as a cocoon, a shield from 1908 and all the rest. October 13 is the anniversary of Steve Bartman reaching over the wall for a foul pop. No Cubs had any clue.

The Cubs seized control in the second. With starter Jason Hammel on deck and the Cubs rallying, Manager Joe Maddon ordered Justin Grimm to heat up in the bullpen. When Miguel Montero struck out, Grimm sat down and Hammel walked to the plate. It all came up Maddon. Hammel rolled a single through the middle. Starlin Castro raced home. Cardinals starter John Lackey stomped off the mound and wove a blanket of expletives. “That’s so Joe,” Epstein said.

Baez made his season debut Sept. 1 and took only 80 major league plate appearances. He started Tuesday because regular shortstop Addison Russell remained out with the hamstring strain he suffered in Game 3. Lackey threw Baez a first-pitch, belt-high fastball over the outside corner. Baez demolished the ball into the right field bleachers. He became the sixth Cub age 26 or younger to homer in the series. Wrigley shook.

These are the Cardinals and this is October, and so they would not cower, even without catcher and soul Yadier Molina, who had to be scratched because he aggravated the torn left thumb ligament he had been playing through. They scored twice in the sixth to tie. Right fielder Jorge Soler, who reached base 10 times in the series, halted the rally with a missile throw to the plate that caught Tony Cruz.

In the bottom of the inning, Rizzo crushed his second home run in as many games off lefty reliever Kyle Siegrest, a blast into the right field bleachers. Schwarber let the crowd relax an inning later, when he provided a souvenir to somebody on Sheffield.

It is a unique season in Chicago, perhaps the start of several great seasons for such a gifted group. There will never be another one like the first one.

“I was talking upstairs with Eddie,” Epstein said. “This is like our first record. You put that first record out, and things blow up. It’s a wonderful time of innocence and exceeding expectations, bursting on the national scene. These guys care so much about each other. It will get complicated as times go by. I don’t think it will get any less special.”