KANSAS CITY — Throughout nearly a decade of losses at Arrowhead Stadium, there may have been no one associated with the Denver Broncos who felt the sting of defeat more acutely than Alex Forsyth.

The Broncos entered Thursday night having lost nine games in a row here, but none was more painful than the gut-wrenching setback that occurred 13 months ago, when Leo Chenal blocked Wil Lutz’s 35-yard field-goal attempt after the linebacker knocked Forsyth onto his backside.

All involved with the loss took accountability afterward. A defeat does not fall on any one person, Forsyth’s teammates insisted. Not in a 60-minute game in which dozens of players from both sides factor into the outcome, in some way or another. Besides, coach Sean Payton insisted after Denver’s 20-13 Christmas victory, the “demons” that have felled the Broncos at Arrowhead the last nine years didn’t belong to this specific team. The way the Broncos have responded to that heart-wrenching loss last November — their 81.3 winning percentage since then is the best in the NFL — is evidence that past curses aren’t exactly haunting them.

But there also may not have been a game ball the Broncos coach has been more eager to hand out after any of Denver’s 13 wins this season than the one he gave Forsyth after he stepped into a starting role at center, on three days’ notice, and helped push the Broncos to the brink of an AFC West title.

“It was a tough trip home (from Arrowhead) last year,” Payton said. “It’s a little life lesson for someone like him, to come back in a starting role, that was pretty cool.”

Forsyth was pressed into action this week as starting center Luke Wattenberg, who had played every snap at the position for Denver this season, landed on injured reserve with a shoulder injury. All Forsyth did on Thursday was help command the middle of the line of scrimmage as the Broncos produced four marathon drives that ultimately produced enough points to win the game.

“This was special. I was just kind of flooded with emotions when I came in here,” Forsyth said after dressing inside the same locker room that could have made a pin drop sound like crashing cymbals after last year’s defeat. “It was great to have my teammates, who have been so supportive with (what happened in) last year’s game, supporting me after that and sticking up for me and sticking with me.”

In some ways, Forsyth’s journey mirrored what it took for the Broncos to finally end the losing streak at Arrowhead Stadium and move to within one victory of clinching the No. 1 seed in the AFC playoffs, something Denver can do by beating the Los Angeles Chargers at home in the regular-season finale next week. The Chiefs and defensive coordinator Steve Spagnuolo presented a deep, two-high shell over Denver’s defense that turned Thursday’s game into a series of grinding, prodding possessions for the Broncos’ offense.

It was how Forsyth picked himself up after last year’s crushing play. The 2023 seventh-round pick made the team out of camp for the third straight year because of practice habits that made him impossible to ignore.

He kept inching forward.

“I would say nobody prepares more in this league than he does,” said Broncos quarterback Bo Nix, who played with Forsyth at Oregon before joining him in Denver in 2024. “He’s one of the most in-depth preparers I’ve ever seen. It’s awesome to play behind him and I knew going into this game he wasn’t going to leave a stone unturned. He was going to (give) the team the best chance of succeeding.”

There were setbacks on Thursday that made it fair to wonder if the Arrowhead spell would still be too much to overcome, even with Kansas City down to its third-string quarterback and dealing with a handful of other key injuries. There was a tipped-ball interception of Nix by Nick Bolton in the first quarter that led to a Chiefs touchdown drive. There were two marathon drives for the Broncos that combined for 30 plays and took more than 16 minutes off the clock in the first half — yet produced only two field goals. There was a 7-6 halftime deficit in a game that kept demanding patience.

“Honestly, it was the exact opposite of what I thought we were going to get,” Nix, whose 1-yard touchdown pass to RJ Harvey with 1 minute, 50 seconds left proved to be the game-winner. “I thought they were going to pressure us like crazy. We got a bunch of two-high zones the whole game. They put a lid on top of it and made it hard to find explosive plays. You’ve just got to inch your way down the field and score on longer drives. We just did what we had to do.”

That was the message Nix preached to his teammates after the Broncos suffered their first loss in three months against the Jacksonville Jaguars in Week 16. With all that would be at stake for the Broncos in their final two games of the regular season, all that mattered, he stressed, was finding a way to win. Payton echoed that statement, saying after Thursday’s win, “It doesn’t have to be aesthetically pleasing.”

It was perhaps fitting then that the game’s most important moment came when Forsyth didn’t even snap the ball.

The play was called “Harrisburg,” and Payton relayed it to Nix as the Broncos approached a fourth-and-2 at the Kansas City 9-yard line coming out of the 2-minute warning. Nix had given the Broncos the lead in the second half with a 9-yard touchdown run on a quarterback draw that was part of an effective rushing night for the playmaking quarterback. But the Chiefs used a 44-yard punt return by Brashard Smith following Denver’s next possession to kickstart a drive that ended in a game-tying field goal from Harrison Butker.

The Broncos were going to be content with kicking a chip-shot field goal to take the lead and let their defense try to stop quarterback Chris Oladokun one more time. But not before they tried drawing the Chiefs offside.

The Broncos broke the huddle and sent Harvey into a wildcat spot in the shotgun behind Forsyth. Nix was split outside as a receiver.

“It’s a no-brainer ‘freeze,’ but it was out of a different formation, one we had never shown,” Payton said, referring to a directive that nobody on the offense move. “We were going to take the delay-of-game (penalty and kick the field goal), so we didn’t have a play. … It’s a unique one because you’re on the road and it involves a heel (lift by Harvey) and (right guard Quinn) Meinerz is barking the cadence out.”

The combination of eye candy in the backfield — fullback Adam Prentice was motioning in front of Harvey — and the hard count coming from Meinerz was enough to force All-Pro defensive tackle Chris Jones to jump into the neutral zone. That triggered a reaction from Meinerz, who stood tall, pointed a finger forward and marched forward, signaling a game-changing first down.

“Hats off to him,” Payton said of Meinerz. “He gets Air Jordans for the offensive line.”

“Quality hard count,” Forsyth said with a grin.

The Broncos still had work to do. Short runs by Harvey and Prentice pushed the Broncos into a third-and-goal at the 1-yard line. Payton put the ball in Nix’s hands on the defining play that followed, the second-year quarterback sprinting to his right with the initial intent of getting Harvey the ball into the flat at the front of the goal line. The rookie running back was initially well covered by safety Bryan Cook, so he continued his route into the end zone as Nix bought more time. At the last minute, Harvey used a subtle shake to break free of Cook in the back of the end zone. Nix fired the ball into the running back’s chest to author his seventh game-winning drive of the season, the most in the NFL.

“I couldn’t see the angle and I heard the cheer,” Payton said. “I just said, ‘Please tell that wasn’t an interception,’ because it was loud enough where I didn’t know if it was a Kansas City cheer. Fortunately, it was a Broncos cheer. I’m anxious (to see the replay). I’m sure it was a heck of a throw and catch.”

RJ Harvey reacts after his fourth-quarter touchdown catch gave the Broncos the lead for good on Thursday. (Jamie Squire / Getty Images)

The Broncos held the Chiefs to 95 total yards before their final drive, yet still had to sweat as Kansas City moved all the way to Denver’s 26-yard line with 25 seconds left on the clock. Firmly out of the playoffs, Chiefs coach Andy Reid almost certainly would have called for a 2-point conversion had his team been able to reach the end zone.

As Oladokun’s pass for Hollywood Brown sailed high in the end zone on fourth down, the Broncos breathed a rare sigh of relief inside Arrowhead Stadium. They were headed for a long weekend that comes with the possibility of an AFC West title by Saturday if the Chargers lose to the visiting Houston Texans. Payton said he’d be fine with winning a division title by that route, calling the prospect of celebrating a West crown from home “relaxing.”

No matter what happens in California on Saturday, though, the latest “biggest game in a decade” is coming to Denver next week. Nix hasn’t beaten the Chargers since entering the league last season. Payton hasn’t defeated Jim Harbaugh in three chances as AFC West coaching rivals. All three have been one-possession losses. Those are demons that do belong to these Broncos.

Can they be vanquished in time to put the cap on this special season?

“It’s playoff time and it’s going to be a playoff atmosphere,” Nix said. “We know it’s going to be tough. I haven’t beaten them. It’s going to be a good nine days of preparation, and on the 10th day, it’s all you’ve got for four quarters, or however long it takes.”