DENVER — For one quarter Sunday, Drew Lock and the Broncos wrote a fairy tale in his regular-season debut.

They took a 14-0 lead on the strength of Lock spreading the football around. He completed nine passes in the first quarter to six different targets. He executed some off-balance throws that displayed his arm talent and the athletic gifts that resulted in basketball scholarship offers from Missouri, Oklahoma State and Wichita State.

There were some misfires — miscommunication on his first pass to Courtland Sutton, an overthrow to tight end Jeff Heuerman. But no one expected perfection from Lock in a debut that came after just nine regular-season practices. But the verve, the swagger and the arm talent were there. He didn’t stumble on his dropbacks from under center. He cleanly fielded every snap from fellow Mizzou product Connor McGovern. He kept the Chargers off-balance. The offense hummed in a way it had not in the previous six quarters, when it accounted for just six points.

And then the Broncos parked the bus for nearly three quarters.

The downfield shots evaporated, replaced by screen passes which took the edge off the Chargers’ pass rush, but also became predictable.

Lock threw for six first downs in the first quarter, going 9-of-13 for 73 yards for an average of 5.6 yards per pass play. He had just two after that, completing 9 of 15 passes for 61 yards after that strong start — with 33 yards and one of the first downs coming on a first-half-ending play to Sutton when the Broncos bypassed a 65-yard Brandon McManus field-goal attempt or a “Hail Mary” toss to the end zone.

Without that pass to Sutton, the Broncos would have averaged just 2.0 yards per pass play in the final three quarters, thanks to a slew of passes that were within 5 yards of the line of scrimmage.

If viewed through a binary perspective in which a “W” in the standings is everything, the day was a total success.

But by going into a shell and effectively playing the Four Corners offense for nearly three quarters, it was also an opportunity lost for the Broncos — an opportunity to push the limits of Lock in a season that will end a without a winning record.

The tactics came as no surprise five weeks after Joe Flacco called out the play-calling for being too cautious and after two consecutive games with red-zone interceptions.

But that doesn’t excuse them now. Not when the rest of the season is about development and data collection.

To learn about Lock, they need to trust the kid.

Trust that he will adapt to disguised looks and pressure from all angles that the Chargers began to mount Sunday, and that will surely multiply in the coming weeks. Trust that he has the mental fortitude and emotional composure to not crumble under adversity, attributes he showed from the moment he was tossed into the fire as a freshman at Missouri.

Trust that he will continue putting in the work away from the field — just as he did while he was on injured reserve, when he went through each practice twice through the Broncos’ virtual-reality system.

And just like he did during OTAs, when he was receiving third-team repetitions behind Joe Flacco and Kevin Hogan and meaningful playing time seemed a galaxy away.

“We stayed up until 1 a.m. every night trying to learn our playbook,” Risner said. “You know, a funny story with Drew — you guys might like to hear — you know, I move in with Drew for OTAs, and I want to earn a spot, so I’m studying. I’ll just be real with you guys: Drew studied later than me every night.

“He would go into his bathroom and write plays up on the mirror and repeat them to himself at all hours of the night. He would go record something on his phone, put it in his headphones, and go and walk and act like he’s getting told the play from the offensive coach walking around the living room saying plays out loud.

“For a while I’m like, ‘Is this dude talking to himself? What’s going on.’ That’s just kind of a little tidbit story that shows who Drew Lock is.”

That’s not only a vignette that shows Lock has a little Will Hunting in him. It also shows his diligence.

It shows why you should trust the kid.

Trust him like Vic Fangio did in the final moments.

After nearly three quarters of keeping Lock in shackles, the Broncos’ robust 14-point lead was gone. While Denver frittered and fretted, the Chargers clawed their way back to tie the score.

With nine seconds remaining, the game was tied and the Broncos sat at their 28-yard line after Diontae Spencer’s 26-yard kickoff return.

As Fangio noted in his postgame press conference, the offensive coaches suggested that Lock take a knee and head to overtime.

“I said, ‘No,'” Fangio recalled.

By explaining this to the media gathered at his postgame press conference, Fangio took the wheel of the bus, started the engine and backed over offensive coordinator Rich Scangarello and his staff.

“First I was looking for a play that could get a big chunk over the middle, bang, [take] a timeout,” Fangio said. “We didn’t like that as much. I said, ‘Let’s go down the sideline and see what happens.'”

Fangio’s instincts were correct.

There was no reason to not be aggressive there. Sutton has shown the ability to make plays in traffic — and draw pass-interference penalties when he can’t. The chances of the Chargers intercepting a pass near the sideline and returning it to where they could score or set up a field goal were minimal. Lock could operate with the option to throw it away if he didn’t see anything.

Fangio decided to trust the kid.

And after Sutton drew a pass-interference call to set up a game-ending Brandon McManus 53-yard field goal, Lock was dancing and darting into Risner’s arms, giddy over a win in his first day as Denver’s starting quarterback.

Decision-making predicated on caution and fidelity to pre-designed scripts is right for quarterbacks who want to play the concerto note-for-note as is presented in its sheet-music form.

It’s wrong for a quarterback like Lock, who can improvise, will adapt and can make a play leap beyond its design to something greater.

But the Broncos’ scheme and decision-making is tailored to a conductor guiding an orchestra. Lock is suited to be the leader of the jam band. When both work, each can be harmonious. But only the jam band can go someplace new and adapt to the moment.

The Broncos must adjust to the quarterback in whose hands their future lies, or neither the team nor its fresh-faced young quarterback will meet their potential.

They must trust the kid.

Maybe Lock will become an elite quarterback. Maybe he won’t. But the way to learn how high he can jump is to keep raising the bar to see if he can clear it.

Lock plays without fear. Scangarello and the offensive staff must play to that daring and swagger — and trust that he’ll continue to meet the challenges of the pro game.

Otherwise neither Lock nor the Broncos will reach their potential for the long term.

Trust the kid.

At 4-8 and with the focus on the future, there is no reason not to.