MINNEAPOLIS — No one player, no one play, no one moment causes a team to lose a 20-0 lead.

But it starts somewhere.

And in dissecting the corpse of the Broncos’ seventh and most heartbreaking defeat of 2019, a 27-23 loss to the Minnesota Vikings at U.S. Bank Stadium, it starts with the final minute of the first half, one snap after Josey Jewell recovered a Ameer Abdullah fumble forced by Will Parks on the kickoff.

With 60 seconds left before halftime and the Broncos up 20-0, the Broncos went in for the kill. Quarterback Brandon Allen spotted Noah Fant on a post route. Two defenders were in the area. One of them, Andrew Sendejo, picked it off.

“Bad throw by me,” Allen said. “Really just trying to force it, wanted to get a big play. So I think that was on me for forcing it.”

“In hindsight, maybe we should have just ran it three times and got our three points and been happy, but you would have roasted me if I did that,” Broncos coach Vic Fangio added.

Was the offense or Allen the primary cause of the Broncos’ defeat? No, although his 61.9 passer rating and a completion percentage of 43.9 percent — which included some missed makeable throws — didn’t help.

But the snowflake that starts the avalanche never seems like a big deal when it falls.

In a game that saw the Vikings commit enough miscues for a month of Sundays, the Broncos ultimately couldn’t capitalize enough to withstand a furious second-half Minnesota rally.

Consider this: The Vikings reached third down six times in the second half. They successfully sustained their drives each time — the first of which came on the initial possession of the second half, when Kirk Cousins snuck for a yard on fourth-and-1 after a third-down stop.

One play later, Cousins began to pick at rookie cornerback Davontae Harris, locating Stefon Diggs beyond Harris’ coverage for a 44-yard gain. Two plays later, with Harris on rookie tight end Irv Smith Jr., Cousins picked at him again, and the Broncos defense had allowed only its fifth touchdown in just over 23 quarters.

No problem, right? The defense, which allowed just four touchdowns in the five games before the bye, would surely rebound. And when the Broncos turned a drive-resuscitating neutral-zone infraction on the ensuing series into a 52-yard march that consumed seven minutes and six seconds before Brandon McManus hit a 41-yard field-goal attempt, it seemed like the threat had passed.

Alas, it was only beginning.

First came the paper cuts — an 18-play drive that saw the Vikings wiggle out of third-and-5, third-and-10 and third-and-14. Just one of the Vikings’ plays on that drive accumulated double-digit yards.

According to pro-football-reference.com, the average time of possession on a drive that takes at least 15 plays and begins in the first 20 minutes of a half this Eason is eight minutes, 27 seconds. Minnesota’s march took nearly two and a half minutes under that average and its march quickest of any of the 39 drives with those parameters so far this season.

Why?

“They just said, ‘We’re going to play hurry-up football.’ And that’s all they did,” cornerback Chris Harris Jr. said.

The Vikings accelerated the tempo. And in doing so, they knocked the Broncos defense out of rhythm.

“They just tried to hurry us up and scramble us, and we got a little discombobulated and communication lapsed.” Harris said.

“Communication wasn’t as well taken care of as it was in the first half, and that obviously showed, with a 27-point half,” added safety Justin Simmons.

Then came more self-inflicted wounds — such as being cute when the moment called for a direct attack. So with third-and-1, 11:57 remaining and a chance to quash all Minnesota momentum by merely stringing together two or three first downs, the Broncos didn’t try to slam it up the gut or send the mobile Allen on a quick sprint to the edge. Instead they opted for the end-around to Noah Fant.

Minnesota wasn’t fooled, and Trae Waynes easily eluded Andrew Beck — who filled in for the injured Andy Janovich at fullback — to force Fant out of bounds for a 5-yard loss. Fant’s other two runs to this point in 2019 resulted in losses of 2 and 5 yards, so this was a fascinating time to try to change the trend.

Finally it was time for the big gashes — touchdown passes of 54 and 32 yards with a missed McManus field goal after a third-and-7 Devontae Booker run off right tackle thrown in.

On the 54-yard Diggs touchdown that whittled Denver’s lead to 23-20, the receiver ran a post route that began when Chris Harris Jr. was in coverage.

“They didn’t lull me to sleep,” Harris said. “We just had a breakup in coverage.”

“There was supposed to be a safety in the middle there, and he got out of position,” Fangio said.

Simmons was “down low” in coverage on Irv Smith Jr. But Kareem Jackson, who was monitoring the route of Bisi Johnson down the left sideline as Cousins rolled in Johnson’s direction, reacted too late to Diggs’ post route.

“When you do that against this type of team [and] they get it rolling like that, it will kill you,” Fangio said, “and that killed us there.”

After McManus’ misfire — on which his foot caught the turf as he swung — the rest seemed academic. Cousins completed four consecutive passes for 68 yards, beginning with a 21-yard screen pass to Dalvin Cook, who finally broke free after being bottled up all day.

It ended with Vikings tight end Kyle Rudolph being wide open in a gap in the Broncos’ zone off a play-action fake. Duke Dawson Jr. and the inside linebackers followed the developing play and moved left, leaving Rudolph uncovered at the Denver 20-yard line.

Rudolph snagged the pass and waltzed into the end zone, and the Vikings led the red-nosed, red-faced Broncos for the first time with 6:01 remaining.

“We would have gotten bailed out if our offense had scored at the end there,” Simmons said, “but you can’t win games like that.”

Of course, the offense, which ended 4 yards short of glory in the final seconds, was culpable, too. Its mind-numbing streak of games without surpassing 24 points extended to 19 in part because the unit got just 17 of a possible 35 points from five drives that entered the Minnesota red zone.

After taking a 17-0 second-quarter lead, the Broncos’ three remaining red-zone forays resulted in just three points.

That’s how you lose when you make it halfway to what would have been the Broncos’ biggest upset in over two decades.

Yes, the Broncos were halfway there. Halfway to a resounding win over one of the league’s most balanced teams. And in some ways, halfway back to relevance and contention.

“I think we’re close,” Fangio said. “But we haven’t gotten over the top well enough yet. We did in our previous game with the stop and then the ensuing first down to close it, but this game, we didn’t get it done. We’ll eventually get it done.”

But here’s the problem: Some teams never get there.

Are losses like these the ones that lead to wins in the future? Or will these Broncos fall amid the rabble of NFL flotsam for which these defeats were a part of an extended pattern of futility?

The Broncos became the 25th team in the Super Bowl era (since 1966) to lose after leading by 20 or more points at halftime. Teams of all levels have lost leads like this; even the 2013 Broncos blew a 24-0 halftime lead at New England en route to Super Bowl XLVIII.

But for where the Broncos stand, the the rebuilding teams on the list illuminate their current plight.

Some of the ones with defeats like Denver’s on Sunday used the loss as a springboard to better things. Take the 1999 Colts, who coughed up a 21-point halftime lead at New England in their second game and then reeled off wins in 12 of their next 14 games.

Seven years later, the Cardinals barfed up a 20-point halftime lead against the Bears in the famous “They are who we thought they were” game. Twenty-five months later, Arizona was in its first Super Bowl, with many of the same players who were a part of that blown lead.

But there are more teams like the 1980 Saints, 1985 Eagles, 1992 Buccaneers and 2005 Texans — clubs for whom such a defeat was part of their path to frustration, not their road to greatness.

Which one will the Broncos be?

That will determine whether Sunday’s heartbreak was a step in the building process or a move towards a dead end.