DENVER — This was the Broncos’ chance.

This was their chance to turn a flicker of a playoff hopes into a bright flame. A chance to get a desperately-needed conference win and earn a tiebreaker advantage on a fellow wild-card contender.

And after the frightening injury suffered by Teddy Bridgewater on a scramble with 5:47 left in the third quarter, it was a chance for Drew Lock to rewrite the narrative of struggles that have defined him since he opened his career with five touchdown passes in his first two games.

This was their chance.

To make the leap from fringe contender to being a team that mattered. For a young quarterback in desperate need of a boost to reshape a career arc that has gone in the wrong direction for most of the last two years.

And they squandered it.

No play encapsulated this more than the Broncos’ only turnover of the their 15-10 loss to the Cincinnati Bengals: Lock’s lost fumble on a second-and-goal run-pass option from the Cincinnati 9.

Trailing by five points with 10:39 remaining in the fourth quarter even a field goal would have helped. Job No. 1 was to avoid giving away the football.

Lock appeared to have confidence running plays that catered to his strengths. And the ill-fated option was one of those calls.

“That’s a play that Drew has been good at since he’s been here,” Broncos coach Vic Fangio said. “That’s one of the reasons we ran it.”

What’s more, it’s a play with which Lock flourished at Missouri, as well.

In his work Sunday, Lock’s brightest moments came when he was able to lean on his comfort-zone plays: specifically play-action from under center, first-read throws — including one to his college teammate Albert Okwuegbunam, one of a pair of 24-yard connections for the ex-Tigers — and 50-50 balls to downfield targets, one of which resulted in the Broncos’ only touchdown of the game on a 25-yard pass to Tim Patrick.

After the game, Lock explained that during the week, he makes notes on the play-call sheet of which ones he thinks he could execute best.

“I dot my plays that I want in case I do get to go into this game,” Lock said. “Here [Mike] Shula, tell Pat [Shurmur], give this to him at halftime,’ whatever it may be, just so they know what I was thinking throughout the week.”

Lock’s long-term history favors using plays like this.

But Lock — by his own admission — read it wrong. And then he lost the football.

“We were reading the ‘C,’ reading the (defensive) end,” Lock said, referring to Bengals edge rusher Khalid Kareem. “They brought cover-zero, the box was stuffed, and I took it upon myself to take the ball. The end (Kareem) shuffled twice.

“Typically when the end shuffles down negative, you kind of have an advantage on them. Kind of shuffled down and came up the field just a little bit enough to where I wasn’t actually able to get outside of him.”

When Fangio was asked whether it was a good play by Kareem or a reckless play by Lock, he replied that it was “probably both.”

“[Lock] decided to keep it and didn’t get it tucked away, and [Kareem] took it from him — which is a good play on that guy’s part,” Fangio said.

“We have to get it tucked away.”

Or make a different decision in the RPO. If Lock had handed the football to running back Javonte Williams, the play might not have gotten very far. But Williams’ ability to accumulate yardage after contact might have given him a chance to turn nothing into something, a skill he displays on a weekly basis.

Instead, Kareem snatched the football and procured it. Lock grazed Kareem just before he was ruled to be down — although that wasn’t confirmed until an instant-replay review. In the moment, a wild pursuit ensued that ended when Lock himself plucked the football from Kareem, allowing Garett Bolles to recover and prevent the giveaway. But replay intervened, and the Bengals took over at their 15-yard line.

Lock’s regret? Not handing it to Williams, who has proven to be a highly-effective ball carrier.

“You know, Shula says it a couple times in the meeting rooms — when in doubt, give it to the professionals,” Lock said. “I’m a professional thrower, not necessarily a professional runner.”

That gave Lock his third turnover in what is now 77 plays of work — roughly equivalent to just under five quarters of action.

Lock’s 2020 giveaway rate of one every 28.1 total QB plays — pass attempts, rushes and times sacked — was unsustainable. This year, it’s one every 15.3 QB plays.

The Broncos had the ball later, but their drives fizzled. Their goal-to-go opportunity was their best chance to win, and as he has too often in his Broncos tenure, Lock lost his grip on the ball.

It hasn’t helped that the Broncos haven’t been able to tweak their practice plan appreciably to get the understudy more snaps mid-week.

“It’s hard to get him more snaps,” Fangio said. “Right now, because of everybody wanting to reduce practice time and all of that for the season, it’s hard to get the backups a lot of snaps. So in that case, we haven’t gotten him enough.”

To his credit, Lock has tried to compensate in other ways, as he’s tried to learn just how to be a backup. But that can only do so much.

“I think you’ve got to do double the amount (of work) that the starter ends up having to do,” Lock said. “Walk through it after practice. I put a patch of turf in my basement, walk through it down there — I did that this summer, so that’s been there. Go over the play call sheet 100 times.”

And, as Lock mentioned, he provides the afore-mentioned notes to Shurmur and Shula. That led to calls that played into Lock’s skill set.

But with one split-second decision and an alert play on the ball by Kareem, all of the progress went asunder — and with it, the Broncos’ playoff hopes landed on life support.

Dec 19, 2021; Denver, Colorado, USA; Denver Broncos quarterback Drew Lock (3) walks off the field after a turn over on downs in the fourth quarter against the Cincinnati Bengals at Empower Field at Mile High. Mandatory Credit: Isaiah J. Downing-USA TODAY Sports

OF COURSE, WITH A BIT MORE OFFENSIVE EFFICIENCY, the defense wouldn’t have been in a position where one lousy play made the difference.

But no matter who lines up at quarterback, the Broncos offense too often leaves the defense no margin for error. So, on a day that saw Denver corral Bengals running back Joe Mixon and contain the Bengals’ dynamic vertical passing game, all it took was one busted play to make the difference.

That play was a 56-yard Joe Burrow-to-Tyler Boyd touchdown pass off of a play-action boot just moments after the Lock-to-Patrick touchdown gave the Broncos their first — and only — lead. It is a staple of the Mike Shanahan/Gary Kubiak offense, whose concepts are all over the Bengals attack that is run by Zac Taylor, a former assistant to Sean McVay, who learned at the feet of Shanahan in Washington from 2010-13.

To see it work it perfectly against the Broncos in their Mile High confines stings like a grapefruit rubbed over an open sore.

“That sucks, man,” safety Justin Simmons said. “Defensively, you’re playing fairly well. (The) offense goes down and scores. We take a 1-point lead. The last thing that you can do is, especially the way it happened, was give up a play like that.

“They saved that play for a time like that.”

And with that, it didn’t matter that Cincinnati’s exquisite rookie receiver, Ja’Marr Chase, had the worst game of his pro career to date, catching just one pass for 3 yards. It didn’t matter that Mixon averaged 3.4 yards per carry, which in this season had been a predictor of a Bengals loss.

Cincinnati had been 0-5 this year in games when Mixon failed to reach 4.0 yards per attempt. The Bengals are 1-5 now.

So it goes for the Broncos this season. They’re 7-7, and, according to data and analytics website FiveThirtyEight.com, they have a 5-percent chance of making the postseason.

They’re 4-4 at home, which means that they’re a Week 18 loss to the Chiefs away from having their third losing home record in the last four seasons — which would match their total in the previous 35.

They were swept by the entire AFC North, which marks the first time since the 2002 realignment that an entire division swept the Broncos.

They are what they many expected to be: a team with a powerful defense, too little offense and an inability to finish — all of which starts with their struggles at the most important position.

A team like that usually only gets one chance in the ilk of what the Broncos had Sunday.

And like a potential touchdown for Courtland Sutton early in the game, it slipped through the their hands.