When it was grim for KC Chiefs Sunday, they reaped what they’ve sown in Patrick Mahomes

Not so long ago, Arrowhead Stadium in the postseason essentially was a haunted house, laden with trap doors and ghoulish twists and turns. So much so that in 2018, after the Chiefs suffered yet another bizarre, shattering loss here, we felt compelled to explore jinxes and curses … and we don’t even believe in that stuff.

Those miserable days (six straight postseason losses between 1994 and 2019) have been steadily purged away over the last few years as the Chiefs transformed the place into a playoff funhouse.

But maybe that anguished history never seemed longer ago and farther away than on Sunday night through a spellbinding game that conjured memories of the most iconic calls in sports history all at once:

Like, “Do you believe in miracles?” and, “I don’t believe what I just saw.”

Because in their AFC Divisional Round game against Buffalo, the Chiefs somehow unfurled a new dimension of the magic that has coursed through these last few seasons to eke past the Bills 42-36 in overtime.

The scene was as riveting as it gets, and surely it was among the most dramatic playoff games in NFL history, but the essence of it all also was something else:

In the enchanted Mahomes Era, and it seems certifiably an era by now, everything isn’t just possible. It’s probable. And maybe even inevitable.

“Everything worked out tonight perfectly,” said Tyreek Hill, who had 11 catches for 150 yards and scored a fleeting go-ahead 64-yard touchdown with 1:02 left in regulation. “Exactly how it was supposed to work out.”

Which is how these became the good old days for the Chiefs and their fans, who on Sunday will play host to the AFC Championship Game for a fourth straight season (an NFL record) after never having done so even once before this streak.

Against the Cincinnati Bengals, they will be seeking their seventh straight home postseason win, a concept that would have seemed absurd a few years ago …

And didn’t look so good with 13 seconds left, when Buffalo took a 36-33 lead on Josh Allen’s 19-yard touchdown pass to Gabriel Davis.

Thirteen seconds.

But even as tens of thousands of Chiefs fans at Arrowhead and millions watching on television let out a collective gasp, perhaps among some choice words and items flung at TVs, the Chiefs methodically regrouped.

They had no impulse to surrender or panic, and, as coach Andy Reid put it, “They didn’t lose trust in themselves.”

And why would they when the indomitable, transcendent Patrick Mahomes is a fundamental part of the equation?

In fact, you could encapsulate what’s happened since Mahomes became the Chiefs starter, and how it has coincided with the Chiefs driving a stake through their 50 years of futility, with what Reid said when he was asked what he told Mahomes with 13 seconds left.

“When it’s grim, be the Grim Reaper,” Reid said. “And go get it. He did that. He made everybody around him better, which he’s great at.”

So the Chiefs, who two years ago became the first NFL team to rally from double-digit deficits in all three postseason games to win the franchise’s first Super Bowl in a half century, simply found a way to reap the grim harvest.

From his own 25-yard line, ho-hum, Mahomes hit Tyreek Hill for 19 yards. After a timeout with 8 seconds left, presto, he fired to Travis Kelce for 31 yards.

After a timeout with 3 seconds left, Harrison Butker thumped a 49-yard field goal that ended a furious flurry of 25 total points in the final 1:54 of regulation to send the game to overtime.

Given the NFL’s inequitable OT framework, when the Chiefs won the coin toss it seemed fated they’d win — which they did when Mahomes hit Kelce for an 8-yard TD at the end of an eight-play, 75-yard drive.

It’s a round earlier, but it was reminiscent in a way of the Patriots winning the coin toss in the AFC Championship Game in 2019: You just sensed Tom Brady would dissect the Chiefs defense.

Now, that sort of aura reverberates from the Chiefs, who won despite safety Tyrann Mathieu missing most of the game after entering the concussion protocol on the first series and won despite falling behind 29-26 with 1:54 left.

They won despite Butker missing a 50-yard field goal and a PAT and despite that curious direct snap to tight end Blake Bell (instead of Mahomes!) on third and 1 at the Buffalo 7 that resulted in a 3-yard loss and settling for a field goal in the fourth quarter.

They won because they didn’t turn the ball over, unlike the four they coughed up in a 38-20 loss to Buffalo earlier in the season. And because this time they got to Allen a couple times (sacks by Melvin Ingram and Jarran Reed) after leaving him unblemished last time.

They won because Reid is a genius, who now has coached the Chiefs to nine of their 17 postseason wins in franchise history, and because general manager Brett Veach and his staff remade the offensive line and acquired Ingram in the middle of the season among their recent feats.

They won because the defense got a lot better during the season, and they won because Hill and Kelce are spectacular talents catalyzed by a once-in-a-generation quarterback.

But most of all they won because they have Mahomes, who somehow still has us all in disbelief multiples times a game with his array of uncanny passes from a zillion release points and the sheer resolve that animates it all.

And continues to reinvigorate the Chiefs and region city itself in some ways.

For context, remember that until three years ago the Lamar Hunt Trophy that is bestowed upon the AFC champion never had so much as been inside Arrowhead before.

The name of the franchise founder, and driving force of the AFL itself, wasn’t affixed to the trophy until 1984, after all. And until 2019, the Chiefs had never played in a home conference championship game to create a reason for it to even pass through here.

The Patriots, of course, took it away with them that year. But the Chiefs seized it the next season on the way to their first Super Bowl in 50 years and again last season on the rare way to back-to-back division titles and Super Bowl berths.

Now they are on trajectory to making Kansas City feel more and more like it’s the rightful home of the trophy when they play Cincinnati with a third straight Super Bowl appearance at stake.

“It’s a special time to be a Chiefs fan,” Chiefs’ president Mark Donovan said after the game.

Especially because of more near-miracles from Mahomes on a night that Hill figures is “definitely another step for him into the Hall of Fame.”

“I’ll remember this,” Mahomes said, “for the rest of my life.”

As will countless others, especially those who appreciate what this was like not so very long ago.