KANSAS CITY, Mo. — This is where it was supposed to go wrong. This is where the Chiefs bid to host their first AFC Championship would start to slip away.

Sammy Watkins, playing in his first game in nearly two months, caught his sixth pass of the day with a minute left in the third quarter. On his way down, though, Watkins lost the ball as Colts linebacker Darius Leonard knocked it loose and then snatched it out from under Watkins.

Down just three scores, the Colts were now on the 20-yard line. The collapse could start now.

But this is another year and another time.

This time, things broke the Chiefs’ way in the 31-13 win against the Colts. It was like decades of karma finally came back around and helped the Chiefs break the cycle of sadness that’s plagued them for the better part of 25 years.

The Colts had the ball for all of two plays before Justin Houston and Dee Ford combined to write their own history and break from the tradition of the past.

Ford sacked Luck at the 20, freeing the ball in the process, and Houston recovered it.

Chiefs ball, Chiefs game.

There was still another quarter to play, 15 more minutes for the worst to happen. But it didn’t.

“I know the city has been waiting a long time for this opportunity,” Houston said.

Indeed. And now, an AFC Championship Game — and a chance to avenge one of their four losses — against the winner of Sunday’s Patriots-Chargers game awaits the Chiefs next week.

Surrounded by more than 76,000 souls filled with nervous energy, the Chiefs came out calm and collected from the opening coin toss. With snow flurries swirling over Arrowhead and piles of the white stuff piled against the retaining walls surrounding the field, the Chiefs executed a game plan that’s worked since early in the season.

Like they did the first nine weeks of the season, Chiefs won the coin toss and deferred. And like many of those times, the defense got off the field quickly, forcing the Colts into the first of four consecutive three-and-outs.

It was the first time since a regular season game against Tennessee in 2013 that the Chiefs defense forced four consecutive three-and-outs.

With Andrew Luck and Colts offense off the field, the Chiefs offense went to work. Patrick Mahomes (27 of 41, 278 yards) orchestrated three straight scoring drives to give the Chiefs a 17-0 lead with 12:13 to go in the second.

Mahomes, a Texas native, said it was the first time he had played a game in the snow.

“I actually thought it was pretty cool,” he said. “I thought I was spinning it well.”

Running back Damien Williams capped the first three-minute drive off with a 10-yard scoring run, and he came up big in the next one, too. That time, he converted the first of four fourth-down attempts by Reid to set up for Tyreek Hill’s 36-yard touchdown.

Williams (24 carries, 125 yards, 1 TD) was Reid’s short-yardage weapon of choice again on the following drive, using him to convert another fourth down that eventually led to Harrison Butker’s 39-yard field goal.

Then, a moment that might’ve started a collapse any other season.

Dustin Colquitt, punting for the first time all game, had his punt blocked — his first since 2013 and only fifth ever. It was the kind of play that could swing the momentum of the game away from the Chiefs in a playoff game, the kind that has before.

But this team isn’t living or playing in the past. With Mahomes, the Chiefs are a team with a future.

The Chiefs didn’t crumple under their misfortune. Instead, Mahomes responded with a four-yard touchdown run to cap a 4 minute 16 second drive in the waning minutes of the first half give his team a 24-7 lead with just less than two minutes to play.

Luck tried to orchestrate an uptempo, less-than-two minute drive. With back-to-back throws, Luck finally helped his team pick up their first first downs of the half. He completed two more first-down passes in the drive to put the Colts inside the Chiefs’ 10-yard-line. With time running out and Luck unable to find someone in the end zone, Indianapolis brought out Adam Vinatieri, usually such an automatic weapon, to kick a field goal with time expiring.

But then the Colts suffered their own special teams miscue as Vinatieri missed a 23-yard field goal — his shortest field goal miss ever. Before that, he was a perfect 97-of-97 from attempts of 23 yards or shorter.

With that, the Chiefs went into halftime with a 24-7 lead and the ball to start the second half.

The Chiefs wouldn’t score after halftime, but they opened with a six-minute drive to chew up clock and keep Luck off the field.

With the offense stagnating, the defense came out and matched the intensity it had in the first half and forced the Colts off the field after a handful of plays. It was a statement game for the maligned defense.

“We’re a family,” Houston said. “We’re going to stick together no matter what people are saying.”

Then, another chance came for the Colts to claw back in the game when Hill muffed the Colts’ ensuing punt.

With the Colts swarming the loose ball, rookie Tremon Smith dove and recovered it. Another potential momentum-swinging play erased.

The Chiefs defense, which has given up just 16 points in the last two games, continued to hold the Colts at bay in the second half, and only allowed Indianapolis to pick up 15 first downs and 263 yards of offense. The Chiefs also kept the Colts from converting any of their nine third down opportunities. Luck completed 19 of 36 passes for 162 yards and a touchdown.

Of course, the Chiefs couldn’t escape all the late-game drama on Saturday. The Colts scored a touchdown with 5:37 left on a 29-yard strike from Luck to T.Y. Hilton, but Vinatieri missed the extra point. With the kicker’s compounded struggles, the Chiefs maintained an 11-point lead instead of a seven-point one.

Then, rookie Darrel Williams sealed the door shut on the Colts, muscling his way into the end zone for his second career touchdown with 2:23 left. Any last shred of tension in the stands evaporated with the hoots and hollers from the crowd as they threw snowballs in celebration and started hitting the exits.

After all, there wasn’t a need to linger for a long goodbye. They’d be back next week.