DENVER -- It all started to go wrong on a day designed to honor Peyton Manning. In 2015 against Kansas City, Manning broke the all-time record for passing yards then shattered to pieces.
He finished the loss on the bench with an injured foot and the unforgettable 0.0 passer rating. The balm for that sting of indignity arrived months later as Manning returned and helped the Broncos win Super Bowl 50. However, that defeat to the Chiefs amounted to the pulling of a loose thread that hasn't stopped unraveling since.
The Broncos have lost nine straight to their rival, outscored by 12 points per game. Six quarterbacks have been saddled with defeats during this skid -- Manning, Trevor Siemian (0-3), Paxton Lynch (0-1), Case Keenum (0-2), Joe Flacco (0-1) and current starter Drew Lock (0-1).
"We are looking to make a statement," Defensive end Shelby Harris said of the Broncos, who haven't eclipsed the Chiefs at home since 2014.
To return to relevance, the Broncos must continue to beat good teams. And if they want to be taken seriously in the AFC West, they have to close the gap on the Chiefs. With the forecast calling for 19 degrees and several inches of snow by the 2:25 p.m. game time, the Broncos insist they will embrace the challenge Sunday.
My Denver7 keys to a Broncos upset:
Darth Vader Time
Drew Lock needs to play like he did last season at Houston -- starting in rhythm, throwing dimes, and no turnovers. He must be better in his progressions, refusing the temptation to focus on one receiver, while scanning the field. He is fearless and maintains confidence without results. But if Lock wants to be Darth Vader as he says, he has to compete with Kansas City's "Star Wars" offense. The Broncos are not beating the Chiefs with field goals. The goal should be 30 points, regardless of the weather.
Run it back
The Broncos rank 25th at 101 yards rushing per game. That does not tell the entire story. The Broncos have posted back-to-back 100-yard rushers in Melvin Gordon and Phillip Lindsay. Sunday, they will play together for the first time since the first half of the opener. Offensive coordinator Pat Shurmur says he will employ them together some. I would have them split time in the first quarter then ride the hot hand. Using Gordon on wheel routes could be critical on third down.
Slow, don't stop, run
Typically the first goal of every defense is stopping the run. But it's likely the Broncos will play zone with seven or eight dropping into coverage. They will be vulnerable on the ground. The Chiefs rushed 46 times for 245 yards last week, both bests for coach Andy Reid during his time in Kansas City. Clyde Edwards-Helaire is a strong candidate for rookie of the year honors. Le'Veon Bell joins him Sunday, and figures to get 5-to-8 touches. Letting the Chiefs run some grinds the clock on their own offense. As such, yards between the 20 can be tolerated if the Broncos can stiffen in the red zone.
It's impossible to blitz Patrick Mahomes. He carves it up with his quick release, weapons and mobility. So if the Broncos bring pressure, it needs to be clinical, working on say two or three occasions. In absence of blitzing, the Broncos must be physical at the line of scrimmage, disrupting routes. Bryce Callahan figures to guard Tyreek Hill (384 yards receiving) even if he lines up outside. Matching up with tight end Travis Kelce (484 yards), whether it's with safeties Kareem Jackson and Justin Simmons or a linebacker, will be a problem. The key is tackling. Kelce has nearly 200 yards after the catch. He will be targeted around eight times. Can Denver keep him under 100 yards and out of the end zone?
Turn the corner
The Broncos will not pull off the upset without winning the turnover battle. The Broncos have produced three takeaways in their past two wins. The Chiefs have only turned the ball over four times this season, including one interception. Denver must punch a ball out in the snow, produce a strip sack, something to flip the field and change the script.
Shots for everyone
It remains the life of the NFL quarterback, trying to balance taking shots while taking care of the ball. Looking back at the Raiders' upset of the Chiefs, Derek Carr let loose on a few third-and-shorts. Lock can't miss when he gets Jerry Jeudy and K.J. Hamler on a one-on-one where they run by the defender. And they must have sticky hands. Denver ranks among the worst in the league in drops. Tim Patrick has been terrific, but he needs help from someone else.
High and tight
Have I mentioned you aren't beating the Chiefs by playing it safely? The Broncos have offensive weapons at their disposal. Hamler returns -- use him on a few jet sweeps and a gadget. And Noah Fant and Albert Okwuegbunam will play together for the first time. Denver stinks in the red zone and on third down. There's no reason that should continue with all of these options. There are plays to dial up, favorable matches to win. It's up to the Broncos to execute them and exorcise this embarrassing losing streak. I believe they will compete, but fall short, setting the stage for two must-win games against the Chargers and Falcons.
RENCK'S PREDICTION: Chiefs 27, Broncos 20