PHILADELPHIA — Corbin Carroll was searching for the words, and he couldn’t find them. The Arizona Diamondbacks — the 84-win, negative-run-differential, underdog-at-all-turns Diamondbacks — were going to the World Series. Minutes earlier, they had vanquished the Phillies, a 4-2 undressing that exposed the flaws of Philadelphia and highlighted the brilliance of Arizona. And Carroll, the Diamondbacks’ indomitable 23-year-old rookie, the sun around which their world turns, was considering how they had done it.

“I don’t even know if there is an explanation,” Carroll said. “It’s just magic.”

Doubted and dismissed when baseball’s postseason began and throughout October — not the standard-level doubts and dismissals but real ones that reflected who they had been — the Diamondbacks have transformed into something different altogether. After winning Game 7 of the National League Championship Series on Tuesday, their second victory in two days at the hellscape for visiting teams that is Citizens Bank Park, they set up perhaps the most improbable World Series in baseball history, a showdown with the similarly surprising Rangers that begins Friday night in Arlington, Texas.

Arizona entered the season with 125-1 odds to make the World Series, with Texas at 50-1. Both teams barely snuck into the postseason as wild cards. And both needed to win Game 7s to get to Game 1, though Arizona’s was far more stomach-churning than the Rangers’ 11-4 blowout of the Houston Astros.

Carroll delivered a tour de force performance Tuesday: 3-for-4 with a pair of runs, RBIs and stolen bases. Following a solid four-inning start from rookie Brandon Pfaadt, the Diamondbacks’ bullpen, long ineffective and maligned, cobbled together five shutout innings from Joe Mantiply, Ryan Thompson, Andrew Saalfrank, Kevin Ginkel and closer Paul Sewald, who retired Jake Cave to send the sellout crowd of 45,397 home lamenting what could have been.

The Phillies thought they were the ones with the magic. They hadn’t lost at home this October, until the Diamondbacks strode into the Bank and robbed Philadelphia’s opportunity at a second consecutive World Series appearance. Loaded with stars, replete with swag, the Phillies looked the part. The Diamondbacks just played it.

“Watching them prior to this series, I don’t think anything scared that team,” Philadelphia first baseman Bryce Harper said. “I don’t think they had any doubts in their minds of coming back here and playing in Philadelphia. I don’t think that team is scared of any situation or any spot.”

That much is true. The Diamondbacks, who finished 16 games back of the Los Angeles Dodgers in the NL West, allowed 15 more runs than they scored during the regular season, the second-worst mark ever for an eventual World Series participant, behind the 1987 Minnesota Twins, whose run differential was minus-20. Arizona’s 84 wins are third fewest for a World Series participant, just ahead of the 83-win St. Louis Cardinals — who won the 2006 title — and the 82-win Mets in 1973. Losers of their final four games of the regular season, the Diamondbacks backed into an NL wild-card spot after the Chicago Cubs and Cincinnati Reds faltered even worse down the stretch.

In the wild-card round, though, Arizona swept the NL Central champion Milwaukee Brewers. In the division series, the Diamondbacks ambushed the Dodgers and swept them too. Arizona still entered the NLCS as distinct underdogs to the Phillies, though it eventually proved itself more than worthy competition.

“When we faced teams like Philly, the Dodgers, Milwaukee, who’s going to believe in the Diamondbacks? No one,” Arizona shortstop Geraldo Perdomo said. “We were silent, and we made damage. Be happy and enjoy what you do. That’s all. That was the message.”

It took some time to take. Over the first two games, the NLCS looked one-sided. The Phillies won the opener 5-3 and filleted Arizona in Game 2 10-0. As the series headed to Phoenix, the Diamondbacks grappled with a troubling reality: lose Game 3 and the series was almost certainly over. Arizona got to Phillies closer Craig Kimbrel to eke out a 2-1 win in Game 3 and chased that with a 6-5 comeback victory that Kimbrel blew spectacularly in the eighth inning.

Following a Game 5 win, the Phillies found themselves in an ideal position: headed home, where they hadn’t lost all postseason, with a pair of chances to win one game. Philadelphia faltered in its first try, with the Diamondbacks finally starting to look like themselves.

Arizona, which prides itself on creating chaos on the basepaths, stole just one base in the series’ first five games. The Diamondbacks ripped four bags during a 5-1 victory in Game 6 and came back in Game 7 ready to do the same.

Little changed before the deciding game. Perdomo and Alek Thomas danced. Carroll maintained his meticulous pregame routine. And Pfaadt, a 25-year-old rookie, simply sat in the chair in front of his locker, preparing for the biggest game of his life.

“We were coming here to play our best baseball, and that’s been the messaging, and it’s been very consistent throughout the course of the year,” Diamondbacks manager Torey Lovullo said. “Today is going to be our finest hour, and I just wanted to make sure that they knew that’s how I felt.”

The offense got started early, a point the Diamondbacks made a priority to quiet the raucous Citizens Bank Park crowd. Carroll, who entered the game with three hits in 26 at-bats during the series, slapped an infield single off Phillies starter Ranger Suarez and moved to third base on a single from Gabriel Moreno, who, like Carroll, is a 23-year-old in his first full season. A Christian Walker fielder’s choice scored Carroll, and Pfaadt followed with a scoreless first.

Diamondbacks players knew that, over the first six games, the Phillies had won the three in which they scored in the first inning and lost the three when they didn’t. Even with that zero in the first, Philadelphia didn’t panic. Alec Bohm, the cleanup hitter whose rough series prompted fans to call for manager Rob Thomson to drop him in the lineup, took Pfaadt into the left-field stands in the second inning to knot the game at 1. Two innings later, Bohm walked and scored on a Bryson Stott double. It looked like the rest of October had here: the Phillies leading, the Bank rocking.

Everything changed in the fifth. Emmanuel Rivera led off with a single against Suarez and advanced to second on a Perdomo sacrifice. Suarez struck out Ketel Marte, the NLCS MVP, bringing up Carroll, who after going hitless in 10 at-bats against left-handed pitchers in the series got his third single of the day off Suarez, scoring Rivera. Thomson removed Suarez, inserted Jeff Hoffman and watched Carroll steal second — one of four Diamondbacks stolen bases for the second consecutive night — and score on a Romero single, giving Arizona a 3-2 advantage.

“Six games ago, you would’ve said I was the hottest center on the planet, so just realizing that it’s always that way in baseball helps,” Carroll said. “You can get caught up in the minute. You can get caught up in all these little things, and that’s what makes baseball so hard.”

“Watching them prior to this series, I don’t think anything scared that team. I don’t think they had any doubts in their minds of coming back here and playing in Philadelphia. I don’t think that team is scared of any situation or any spot.”

Phillies first baseman Bryce Harper

The Diamondbacks added another run in the seventh when Perdomo singled, went to third on a Marte double and scored on a Carroll sacrifice fly to extend the lead to 4-2. Philadelphia had its chances. Saalfrank, a rookie, walked Cristian Pache and Kyle Schwarber with one out in the seventh, prompting Lovullo to call on Ginkel. He induced flyouts from Trea Turner and Harper — who were a combined 0-for-8 — before striking out Bohm, Stott and J.T. Realmuto in a brilliant eighth inning.

“Harper lives for those moments,” Ginkel said. “Every single guy in that lineup is so good. And so with Harper, I had to mix a lot, and I’m like, I don’t want to leave anything in the zone to give him an opportunity to get a run in or worse. Even if it’s bad contact, he still hits it hard. And he’s a generational great, honestly. So I got the better of him, and it was great. And I think that eighth inning, going out and executing my game plan, put us in the spot for Sewald.”

As Sewald added, “This guy makes my life easy. I get 7, 8, 9 with a two-run lead because this guy gets everybody out.”

Acquired at the trade deadline, Sewald helped stabilize Arizona’s bullpen. Three weeks later, the team signed Thompson, who had been released by the Tampa Bay Rays. Soon thereafter, it called up Saalfrank, a lefty who didn’t allow a run in 10 regular-season appearances. The bullpen’s ascent has been a microcosm of the rest of the Diamondbacks, and when Sewald came on to face the bottom of the Phillies’ order, he induced three flyouts, including the final one that Carroll squeezed to clinch the pennant.

The celebration started quickly and didn’t stop. While the Phillies were bemoaning their fortunes — “It’s a disgusting feeling, honestly,” said Nick Castellanos, who went 0 for his last 24 in the series — the Diamondbacks reveled deep into the night.

Around 2 a.m., after lots of beer had been consumed and empties littered the floor, a group of staffers started cleaning the mess. In the middle of it was Mike Hazen, the Diamondbacks’ general manager who traded for Sewald, drafted Carroll and constructed this team of snakes that slays dragons. He grabbed metal bottles and chucked them into waste receptacles, never above doing the hard work, a tenet that his team has embraced all October.

Effort. Talent. A little bit of magic. And now, once again, the Arizona Diamondbacks in the World Series.