The Broncos might be the worst team in the AFC West. The defense remains one of the best in the NFL but the offense -- starting with the offensive line and working back from there -- is a huge liability, one that goes a long way in explaining why this team ranked 20th before Sunday's beatdown at the hands of the Chargers.

Below, we look at particulars of how the Broncos got shut out for the first time since 1992, back when John Elway was the quarterback and Trevor Siemian was 11 months old.

Heading into the game, the Broncos were 3-2 and a game-and-a-half behind the Chiefs in the division. The Chargers, meanwhile, were looking for their third straight win after opening the season with three straight losses. The Chargers' plan was to stop the Broncos' running game, something they struggled to do against the Raiders the previous week when they allowed 109 yards.

"We walked through every run fit [during Thursday's practice]," defensive coordinator Gus Bradley said last week. "It's just an understanding and we keep repeating it over and over again."

Well, something took because the Broncos managed just 69 yards on the ground and averaged 3.6 yards per attempt.

The Broncos' offensive line, which couldn't protect Siemian or open running lanes, meant that Herculean individual efforts would be needed just to sustain drives. Neither Siemian nor the running backs were up to the task -- and a lot of credit has to go to the Chargers defense.  

Broncos' first series

This series set the tone. The Chargers held the Broncos to six yards on their first two carries, and on third-and-4, Siemian was pressured, threw an off-balance, ill-advised pass that found tight end A.J. Derby, who promptly fumbled. 

Result: Lost fumble

On the Chargers' first offensive possession, Denver's defense, which did its part to keep the game from becoming more of a spectacle, stonewalled Los Angeles' offense four straight times, including on fourth-and-goal from the 1-yard line.  

Broncos' second series

Siemian failed to set his feet on any attempt during the first two drives, where he was 1 of 3 for 23 yards. The second drive stalls after six plays and 18 yards and then this happened:

Related: Is this sound coverage by the Broncos' punt team?

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CBS/NFL

Result: Punt return for touchdown

Broncos' third series

Siemian is finally able to set his feet on the first throw of the third drive, which goes for four yards. A short run leaves the Broncos in third-and-3, and in an attempt to draw the Chargers offsides, Derby's day gets worse when he's flagged for a  false start. Siemian then airmails his intended target on a sideline route.

Result: Punt

Broncos' fourth series

After a first-down throw to Demaryius Thomas, the Broncos return to the running game. Jamaal Charles rushes for one yard and a play later gains two more on a swing pass. A third-down quick pass to Thomas is blown up before it has a chance to develop and he loses four yards. 

Result: Punt

Broncos' fifth series

Running back C.J. Anderson loses two yards on the opening carry. On the next play, the pocket collapses around Siemian, who steps up, throws off balance and should have been intercepted. On third-and-12, suspect pass blocking again bothers Siemian, who runs for the first down ... except the Broncos were called for holding on the play. A screen pass on third-and-longer comes up short and, you guessed it ...

Result: Punt

The Chargers answer with a nine-play, 65-yard drive that ends in a touchdown to give them a 14-0 lead seven minutes to go in the first half.

Broncos' sixth series

A 4-yard pass play is followed by a run for no gain, which is followed by Siemian getting absolutely destroyed by Melvin Ingram. My heavens.

Silver lining: Siemian didn't die and Ingram was flagged for leading with the crown of his helmet, giving the Broncos a rare first down. Three plays later, Siemian hooks up with Devontae Booker for a 16-yard gain and it's another third-down conversion. On the very next snap, the offensive line breaks down again, Siemian scrambles to his left and a strip-sack ensues. Chargers ball.

Result: Sack, lost fumble

Broncos' seventh series

Siemian tries to force a throw to Thomas that falls incomplete, and C.J. Anderson drops a pass on second down. The Chargers bum-rush the Broncos' offensive line again on third-and-long, Siemian panics, tucks and run for a six-yard gain. Altogether now ...

Result: Punt

Broncos' eighth series (last series of first half)

With just under two minutes to go in the first half and the ball on the Broncos' 37-yard line, Siemian begins the drive by taking a sack. Two completions later, Denver is still short of the sticks and ...

Result: Punt

Not-so-fun fact: The Broncos didn't cross midfield in the first half.

To recap:

Broncos' ninth series (first series of second half)

It was perhaps fitting that this drive started on the Broncos' 1-yard line. It was also fitting that the running game remained a nonfactor and that Siemian was sacked by Joey Bosa. You won't believe this but after failing to convert on third-and-long, the Broncos had to ...

Result: Punt

Broncos' 10th series

The Broncos roll Siemian to the right on first down, he finds Thomas along the sideline and when he's finally brought down 81 yards later ... there's a flag on the field. Because god forbid the Broncos can have nice things. Thomas was called for offensive pass interference, a development with which he did not agree.

Siemian came back with two short completions and on third-and-4 he dropped back to pass again, was hit as he threw and for the second time in the game, should have been easily intercepted. Instead, the Chargers defender dropped the pass and, well, you know the deal ...

Result: Punt

Broncos' 11th series

Siemian again rolls right on first down and woefully underthrows tight end Virgil Green for what would have been a 30-yard gain. Incomplete. The Broncos finally show life with three straight first downs but then Siemian is sacked by Bosa. Two plays later, on third-and-6, Siemian again throws an off-balance downfield pass that is almost intercepted. The Broncos go for it on fourth down and Siemian does what he couldn't the play before: throws that pick:

Hey, at least it wasn't a punt.

Result: Interception

The Chargers take 10 plays to convert the turnover into points, which come in the form of a 42-yard Rivers-to-Benjamin touchdown.

Good news: Denver gets the ball back! Bad news: Denver gets the ball back!

Broncos' 12th series

After a good return, the Broncos start on the Chargers' 43-yard line. Three straight Siemian completions gets Denver down to the 11-yard line, and two straight Denver penalties follow, setting up first-and-25 from the 26. Two short passes later set up third-and-long and, like clockwork, Siemian gets blown up in the backfield and fumbles in the process. The Broncos recover and on fourth-and-26 a screen pass comes up 11 yards short of the end zone.

Result: Turnover on downs

Broncos' 13th series

Denver gets the ball back one last time with under a minute to go. Siemian completes three meaningless passes in the middle of the field as, mercifully, the clock runs out. 

Result: Chargers 21, Broncos 0

Certainly some credit goes to the Chargers' defense, which contained the running game, disrupted the pass-blocking schemes and harassed Siemian all afternoon. But it's not like the Broncos' defense didn't play well either. That unit allowed just 242 total yards, held the Chargers to just 3 of 12 on first down, and stymied them at the goal line to end their first drive. In fact, looking at conventional stats, there wasn't much difference between the two defenses:

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The issues arose on special teams and with turnovers, and that starts with Siemian, who came into the game ranked 22nd in QB efficiency, according to Football Outsiders. Siemian wasn't the sole reason for the outcome and first-year coach Vance Joseph acknowledged as much when asked if he thought about benching his quarterback.

"No, I did not," he said, adding: "He's our quarterback. It's a two-score game for most of the game so why make a change when we're still in the game? We had some good plays called, we missed some. We had three turnovers on the day, which is way too many. We had a punt return for a touchdown, which can't happen. It wasn't simply on Trevor."

Wide receiver Bennie Fowler probably put it best Monday morning. 

"We beat ourselves," he said, via the Denver Post. "We had some penalties. We had some missed timings in the red zone. We had a lot of things that can be corrected. We have to take the good with the bad and move forward."

But it's one thing to identify the problem and something else entirely to do something about it. The Broncos are a mediocre team with a mediocre quarterback leading a mediocre offense and a top-10 defense asked to make up the difference. So far, it hasn't worked, and it's unclear things will magically sort themselves out in the coming weeks.

"It falls on the coaches and the players," Joseph said Monday. "Not just Trevor, but everyone. When you have mistaken or negative plays on offense, it usually falls on two or three people, not just the quarterback. But, obviously, he's the quarterback and at the end of the day, it definitely falls on his shoulders because he's the quarterback. Mike (McCoy) is the (offensive) coordinator, and I'm the head coach. It definitely falls on those individuals first, but it's everyone. We have to coach better and play better in all three phases."

Things could get much worse before they get better; the Broncos travel to Kansas City (5-2) and Philadelphia (5-1) for their next two games before hosting the Patriots (5-2). There's a chance they'll be 3-6 ahead of their Week 11 game against the Bengals.

The last time Denver was three games under .500 in November was 2011. That season, some guy named Tim Tebow took over the starting job in Week 6 (incidentally, a game after the Broncos lost to the Chargers) and led the team to an 8-8 record, which was good enough for the AFC West title, and a playoff win over the Steelers. 

Tim Tebow ain't walking through that door in Denver.