KANSAS CITY, Mo. -- After Wade Davis retired Josh Donaldson for the final out of the American League Championship Series late Friday night, the Kansas City Royals gathered in the middle of the infield to celebrate a pennant and receive their league championship trophy. They basked in the music, the camaraderie and the admiring eyes of 40,494 fans before retiring to the clubhouse and an alternate reality of goggles, plastic wrap and unbridled joy.

As they exulted and sprayed, reflected and reveled, the air was soon thick with the smell of champagne and unfinished business.

The 4-3 final score confirmed the Royals had checked off another item on their 2015 to-do list. They've joined the 2000-2001 New York Yankees and 2010-2011 Texas Rangers as the third team to win back-to-back American League pennants in the new millennium, and they'll begin the World Series on Tuesday night at 8:07 p.m. ET vs. the New York Mets at Kauffman Stadium.

The Royals came into the season on a mission to prove they were not a one-hit wonder, which helped fuel a drive to a second straight World Series berth that culminated with a thrilling Game 6 triumph. Rob Carr/Getty Images

If the Royals want a little extra motivation to go the distance, they need only reflect on the end of the 2014 season, when Madison Bumgarner turned bionic and a Salvador Perez pop fly settled into Pablo Sandoval's glove in a Game 7 loss to the San Francisco Giants on this very diamond. The crushing void of that experience would carry them through every challenge that awaited them this season.

Maybe it took an outsider to truly appreciate the depth of their resolve. Pitcher Chris Young, who signed a one-year contract with Kansas City in early March, joined the Royals at their spring training complex in Surprise, Arizona, and saw a determination beyond anything he had witnessed in 11 major league seasons.

"I was the late guy, showing up March 6th or 7th, and I walked into the clubhouse and I could feel the hunger from day one,'' Young said. "I called my wife and I said, 'This team genuinely wants and believes they're going to win the World Series.' I told her, 'I've never been around a group that has that hunger this early.' And here we stand 6½ months later with this opportunity to go and represent the American League. It's remarkable.''

The final step of the journey -- to this point -- was chock-full of drama and considerably more anxiety than the Royals would have preferred.

Sporting a 3-2 lead in the series and intent on closing it out, the Royals seized the early initiative against Toronto starter David Price with solo homers by Ben Zobrist and Mike Moustakas (the latter of which survived a replay review). When Alex Rios delivered an RBI single to make it 3-1 through seven, the stage was set for Kansas City's bullpen to nail things down in orderly fashion.

But what's the fun of doing things that easily? With Davis rested and ready to go, Kansas City manager Ned Yost tempted fate and began the eighth inning with setup man Ryan Madson, who had pitched very well during the regular season but not well enough to prevent fatalistic Royals fans from lining up and sharing their anxiety on Twitter in Game 6.

After a leadoff single by Ben Revere, Madson served up a 96 mph fastball that Jose Bautista powered over the left-field fence for his second home run of the evening to tie the score at 3-3. And Yost, who has largely moved past the human piñata status that defined much of his early tenure in Kansas City, was suddenly destined to receive the Matt Williams treatment on social media.

In hindsight, Yost had his reasons. He knew that rain was on the horizon, and he didn't want to bring Davis into the game only to lose him to a delay. "I was going to put Madson in the ballgame. But the plan was, if anybody got into scoring position, Wade was coming in,'' Yost said. "Then Madson ends up giving up the home run. He made a mistake on a pitch up in the zone, and Bautista kills those pitches.''

"I've seen Bautista come up in the past, and he throws the ball to second base on that same play. [Cain] turns on the afterburners, and it's going to take a perfect throw to second and then a perfect throw home in that situation."

No matter. Lorenzo Cain drew a leadoff walk against Roberto Osuna in the bottom of the eighth, and Eric Hosmer followed with a line drive into the right-field corner. As Cain churned into third base, he was greeted by a windmilling Mike Jirschele, who waved him home with the go-ahead run.

This is the same Mike Jirschele who was thrust into the spotlight last year for (correctly) holding Alex Gordon at third base in the final, pivotal inning of the World Series finale. Last October, Jirschele endured the ultimate third-base coach's nightmare of being the center of attention for all the wrong reasons. This time, he was hailed for doing his homework and making a gutsy, proactive call to score the game winner.

"I've seen Bautista come up in the past, and he throws the ball to second base on that same play,'' Jirschele said. "[Cain] turns on the afterburners, and it's going to take a perfect throw to second and then a perfect throw home in that situation.''

Davis, who had come on to bail out Madson in the eighth, returned for the ninth despite a 45-minute rain delay. During the down time, he rode a stationary bike, applied heat packs to his arm and shoulder and threw in an indoor cage to stay loose.

"In a normal game, he wouldn't have come back out,'' Royals pitching coach Dave Eiland said. "I kept saying, 'How do you feel?' If he had given me a little bit of a crack, I would have pulled the cord on him. But he didn't. He was very convicted and sure about himself, so we went with it.''

All Davis had to do to clinch the victory was retire Donaldson, the American League MVP front-runner, with men on second and third and preserve a one-run lead. He achieved that goal with his 30th pitch, a 95 mph heater that Donaldson grounded to third for the 27th out.

So now the Royals move on in search of the ultimate prize. As the baseball experts compare them with the Mets, the Royals' biggest question mark is going to be their starting pitching. Edinson Volquez has performed well in the postseason, but the Royals don't know which Johnny Cueto will show up on a given night, and Yordano Ventura's maturity and focus don't always match his eye-popping stuff.

Still, the defense is airtight, and the bullpen remains a strength despite the loss of closer Greg Holland to Tommy John surgery three weeks ago.

The real October revelation has been Kansas City's offense, which has a knack for putting balls in play and a gift for summoning rallies and uprisings out of thin air. The Royals have averaged 5.7 runs per game and hit .271 as a team with a .777 OPS in the postseason, and they've consistently elevated the caliber of their at-bats against late-inning relievers with games on the line.

The bold decision to send Lorenzo Cain home on Eric Hosmer's eighth-inning single paid off with the go-ahead run in Kansas City's series-clinching ALCS Game 6 victory. AP Photo/Paul Sancya

The Royals put together a six-run rally to steal a game from Houston late in the division series, and they overcame a 3-0 deficit against Price to win Game 2 of the ALCS by a 6-3 score. Against that backdrop, scoring a lone run to break a tie against Osuna on Friday was mere child's play.

"There were so many games this year, you'd sit in the dugout or the bullpen watching, and the other team's starter would have 40 pitches after four innings,'' pitcher Kris Medlen said. "He's cruising along, and all of a sudden -- bam bam bam. There's something about being in the moment. Every single guy. Laser focus. They just lock in on every pitch. Each guy feeds off each other, and that's what you need to do to string together hits the way we do.''

Simplistic as it sounds, the Royals continue to thrive because no one gets wobbly in the knees when the outs start counting down and the magnitude of the at-bats ratchets up exponentially.

"I saw a sign in the stands tonight that said, 'Keep the line moving,''' left fielder Alex Gordon said. "We don't try to be the hero. We just try to put quality at-bats together. No one is afraid of being up in that spot. One through nine. No guy is going to shy away from it.''

The Royals embraced the challenge of repeating in February, when they weren't getting much love from preseason prognosticators, and they've outlasted Houston and Toronto clubs that presented stiff challenges in the first two rounds of the postseason.

After 162 regular-season games and 11 more in the playoffs, they're back in the World Series and in position to write a different ending from the one that brought them to their knees in October 2014. From the moment pitchers and catchers arrived at spring training, that's all they ever wanted.