Six stories explaining Denver’s 16-game losing streak to KC.

On an overcast 87-degree September evening in 2015 at Arrowhead Stadium, the Denver Broncos and the Kansas City Chiefs did what they have done for decades in a rivalry that dates back to the AFL’s earliest days — they slugged it out.

In the game’s closing seconds, Broncos linebacker Brandon Marshall knocked the ball free from Chiefs running back Jamaal Charles and Bradley Roby recovered and returned it 21 yards for a touchdown. The Broncos — who would go on to win Super Bowl 50 five months later — had pulled off an improbable 31-24 win for their 15th consecutive AFC West road victory.

But the current Broncos-Chiefs rivalry, or what’s left of it, has not reflected that era for several seasons.

The Broncos are 0-16 against the Chiefs since that night and Sunday (4:25 p.m. ET, CBS) is their next chance to break the streak. A cavalcade of coaches, quarterbacks and losing seasons have followed, and no losing streak signifies Denver’s troubles more than the one led by Chiefs 28-year-old wunderkind Patrick Mahomes, who is 12-0 against Denver.

Broncos coach Sean Payton got his first glimpse of it two weeks ago in Kansas City. There have been routs, big plays and small ones, close calls and last-second kicks, just no Broncos win.

“Just hard to believe,” former Broncos cornerback Chris Harris Jr. said. “That’s a long, long time.”

Or as former Chief, and now former Bronco, Frank Clark put it in training camp: “In a rivalry, it’s competitive, true or false? Until (the Broncos) become competitive enough, we have to beat the team.”

Things continue inching perilously close to the 20-game losing streak the Buffalo Bills had to the Miami Dolphins from 1970-79, the longest in the NFL’s post AFL-NFL merger era.

These six games encapsulate some of the toughest moments of the losing streak:

Loss No. 1: Nov. 15, 2015, Chiefs 29, Broncos 13

This one started it all. It also revealed the severity of quarterback Peyton Manning’s foot injury, which he later would disclose was a partial tear of his plantar fascia. He went on to miss seven starts.

Manning was 5-of-20 passing for 35 yards with four interceptions when coach Gary Kubiak pulled him with 6:34 left in the third quarter. The game included one of the most uncomfortable game stoppages in memory as Manning had been honored after his first completion moved him past Brett Favre as the league’s all-time passing yardage leader. Manning already had an interception and had lost a fumble in the game before the 4-yard completion to Ronnie Hillman broke the record.

“I was protecting him because I was worried about him,” Kubiak said then of pulling Manning. “I am disappointed in myself, this one is on me. I should have probably made the decision not to play him.”

The Chiefs led 29-0 early in the fourth quarter. The Super Bowl 50 win, in Manning’s final game, would come in February, but hidden somewhere in the confetti was the first domino of the ongoing streak.

Loss No. 3: Dec. 25, 2016, Chiefs 33, Broncos 10

Nothing signals doom quite like a nose tackle throwing a touchdown pass.

Chiefs coach Andy Reid dialed up the play for Dontari Poe, listed at 346 pounds, as the final score in a never-in-doubt rout.

Poe, who had been used as a short-yardage blocker/runner in goal-line situations, took a direct snap, took a few steps toward the line of scrimmage, jumped and tossed a 2-yard touchdown pass to Demetrius Harris.

“I’ve learned this over time, You can’t score enough points against these teams,” Reid said after the game. “We don’t take anything for granted. We’re going to score as much as we can do it.”

At the time, Poe was the first defensive player to throw a touchdown pass in a game since 1981.

“I would have saved it for another game, if I was them,” Harris said then. “They might need it more later, and now it’s out. I mean, you don’t like that stuff, but we’ve won the AFC West every year, man. It’s their first chance to actually win it — about time somebody beat us.”

Loss No. 5: Dec. 31, 2017, Chiefs 27, Broncos 24

Snow flurries swirled for the season finale as the Broncos closed out their second consecutive playoff miss with a 5-11 finish.

But this day would be its own red-letter affair for the Broncos as Reid gave a then-22-year-old rookie named Mahomes his first career start.

The quarterback went 22-of-35 passing for 284 yards with an interception. But he also put together his first game-winning drive, taking the Chiefs from their own 21-yard line with 2:45 to play into position for Harrison Butker’s 30-yard game winner on the final play.

Mahomes was sacked on the first play of the drive, but then went 4-of-5 for 52 yards with a 4-yard run thrown in during the 11-play affair.

Broncos cornerback Aqib Talib’s words have been true ever since: “He’s going to be a problem, you can see it, he ain’t afraid.”

Loss No. 8: Oct. 17, 2019, Chiefs 30, Broncos 6

Mahomes was 10-of-11 passing with a touchdown when, on a fourth-and-1 from the Broncos 5-yard line with 10 minutes left in the first half, Mahomes tried a sneak. He gained two yards, but suffered a dislocated kneecap.

“Not too many people get hurt on a sneak … it’s a freak thing,” Reid said that night.

Enter Matt Moore, who had played in all of 14 games in the previous four seasons combined. He promptly went 10-of-19 passing the rest of the way for 117 yards including a 57-yard touchdown pass to Tyreek Hill.

Broncos quarterback Joe Flacco, signed that year with the idea he might repair the Broncos’ woes at the position, was sacked eight times.

Loss No. 9: Dec. 15, 2019, Chiefs 23, Broncos 3

This one simply broke the unbreakable.

Nobody in and around the Broncos routinely exuded optimism more than linebacker Von Miller. Miller was rarely without a smile and hardly ever missed a practice drill, let alone a practice, in his time with the Broncos.

But after this rather routine dispatching of the Broncos that included a 340-yard, two-touchdown day from Mahomes and helped the Chiefs clinch their fourth consecutive division title, a dispirited Miller looked like a player who believed it might not get better.

“I don’t know how we got to this point,” a grim Miller said after the game. ” … It just defeats my soul to go out there and play the way we play and lose the way we lose … I’m ready to bring whatever we had in the past back. I want that back.”

Loss No. 15, Jan. 1, 2023, Chiefs 27, Broncos 24

Jerry Rosburg, an interim coach who had been hired early last season as a consultant on clock- and game-management issues, almost snapped the streak to close out last season as the replacement for the fired Nathaniel Hackett.

Denver, who had a confounding offensive pass interference flag thrown on wide receiver Courtland Sutton early on after he had fought through double coverage for a 44-yard catch that was waved off, had a 17-13 lead with under seven minutes to go in the third quarter.

But alas, the Chiefs scored 14 fourth-quarter points, and the Broncos, trailing 27-24 with 1:21 to play, failed to convert a fourth-and-2 from their own 45-yard line as quarterback Russell Wilson was sacked for the league-leading 53rd time that season.

“I’m heartbroken for (the players) … it wasn’t good enough, I’m heartbroken for them, they deserve a win,” Rosburg said. “This whole streak thing … that I think is just fantasy, has got to stop and the only way it’s going to stop is if we stop making errors down the stretch in the game. (But) they fought until the very end.”

Can Payton put an end to the losses?

There are times when Payton, seven games into his Denver tenure, has bristled at discourse over past success or current streaks. On Sunday, after the Broncos’ victory over the Green Bay Packers, he was quick to swat away a question about how Denver let 10 consecutive halftime leads get away up until the Week 7 win.

“Who? My team hasn’t blown 10 straight. You said, ‘Your team’. Let’s start and say, ‘the Denver Broncos, historically’ — (but) I don’t pay attention to that, I don’t pay attention to that, I don’t pay attention to it,” Payton said. ” … The good teams don’t have those issues.”

But this streak, against a Chiefs team with a generational quarterback, is Payton’s now, along with the players, the coaches and everyone who came before them, who’ve been fired, released or simply moved on without a win over Kansas City.

Miller, who was traded by the Broncos, won another Super Bowl ring and signed in Buffalo in free agency, once said about the streak: “It’s got to end sometime, doesn’t it?”