NEW YORK — They worked all season to take one more step in the World Series.

Eric Hosmer wouldn’t wait any longer.

A daring dash by Hosmer tied the score in the ninth, and those bound-and-determined Kansas City Royals rallied yet again to beat the New York Mets 7-2 in 12 innings early Monday for their first championship since 1985.

One agonizing win from ecstasy last year, this time the Royals reign after their latest incredible comeback and a go-ahead hit in Game 5 from Christian Colon, maybe the most unlikely player in uniform.

So go ahead and crown ‘em, Kansas City! The job is finally done.

“From Day One, there was no doubt in my mind that they wouldn’t accomplish it. There was no doubt in their mind that they wouldn’t accomplish it,” manager Ned Yost said. “It’s just a special, special group that doesn’t come around very often.”

Down 2-0 in the ninth, Kansas City fought back against two of the top arms on the pitching-rich Mets: Matt Harvey and Jeurys Familia. And the Royals won it not with power at the plate but instead an aggressive sprint home by Hosmer on a groundout, a three-run double from Lorenzo Cain, a couple of crucial steals.

Consistent contact, keep the line moving.

“I couldn’t have written a better script,” Yost said.

That’s how Series MVP Salvador Perez and the Royals became the first team since the 2002 Angels to come from behind in all four World Series wins, according to STATS.

That’s how they washed out the bitter taste of last year’s Game 7 loss to San Francisco at home, an October heartbreak that drove the Royals to their singular focus all season.

Never waver. Win it all. Wipe away the pain.

“Kansas City is No. 1. Who cares about what happened last year?” Perez said.

To get back where they were last fall — 90 feet from tying the Giants in the ninth inning — the Royals played more than 50,000 pitches of baseball and flew nearly 30,000 miles while crisscrossing the country.

Now, this group of homegrown favorites who revitalized a floundering franchise, Mike Moustakas and Alex Gordon and Hosmer to name a few, can finally rest and rejoice.

Not to be forgotten, major contributions from new additions assembled by general manager Dayton Moore like Ben Zobrist, Johnny Cueto, Kendrys Morales, Chris Young and Alex Rios.

All together, they take their place in Royals history alongside Hall of Famer George Brett, Bret Saberhagen, Willie Wilson and those unexpected champs from 30 years ago.

“It’s kind of good that these guys have their own identity,” said Brett, a team executive. “It’s going to be fun comparing the two teams.”

Next up, Tuesday’s parade in Kansas City to celebrate the club’s second title, capped with a party at historic Union Station.

With no margin for error, Harvey put the Mets’ last hope in his hands and hung on as long as he could. After eight scoreless innings, he pushed to pitch the ninth and finally faltered.

“Obviously, I let my heart get in the way of my gut,” manager Terry Collins said. “It didn’t work. It was my fault.”

New York slugger Yoenis Cespedes exited with knee pain but Curtis Granderson hit a leadoff homer, his third long ball of the Series, and the Mets managed two runs against heavy-hearted Royals starter Edinson Volquez, pitching one day after returning from his father’s funeral.

But for these resilient Royals, no deficit was too large, no time too late.

“We never quit. We never put our heads down,” Perez said. “We always compete to the last out.”

Perez looped a leadoff single in the 12th off losing pitcher Addison Reed, and pinch-runner Jarrod Dyson stole second. One out later, Colon stepped in as a pinch-hitter for his first plate appearance since the regular-season finale Oct. 4.

Hardly rusty, he lined a 1-2 pitch into left-center and pounded his chest at first base.

“He’s a winner,” Yost said.

Alcides Escobar added an RBI double, and Cain’s bases-loaded double off Bartolo Colon broke it open.