Are the Denver Broncos a threat to the New England Patriots?

As the NFL reaches the halfway point of its season, three teams in the AFC remain undefeated -- the Denver Broncos, Cincinnati Bengals and, of course, the New England Patriots.

Both the Patriots and Broncos are set to meet in Week 12 on Nov. 29. Given both teams' schedules -- the Pats face the Washington Redskins, New York Giants and Buffalo Bills while the Broncos have the Indianapolis Colts, Kansas City Chiefs and Chicago Bears -- it's entirely possible that both teams enter this game undefeated.

The Pats' offense is in the midst of something only seen twice before in NFL history, as it's averaging 35 points per game through their first seven games of the season (something the team did in 2007, and the New Orleans Saints did in 2009). Meanwhile, the Broncos' undefeated record is primarily creditable to their defense.

So far, the Broncos allow just 261.1 yards per game and teams can only average 171.9 yards on them through the air, both of which lead the league. Compare that to a Patriots offense that averages 414.6 yards per game (5th) and 329.3 passing yards per game (2nd). As Pro Football Focus' Sam Monson said following the Broncos' 29-10 dismantling of the Green Bay Packers on Sunday:

It’s time to start appreciating that this Denver defense is something a little bit special. Coming into Sunday night’s game I thought the Packers might be able to get the W because Aaron Rodgers would get enough done against the Broncos to top what Peyton Manning could achieve against Green Bay’s defense, but boy was I wrong.

The Broncos defense it turns out is much, much better than I gave it credit for, and I was already giving it credit for being the best in the league by some margin.

Now we need to start thinking of it in all-time great terms. 

PFF goes on to cite the 2013 Seattle Seahawks, one of the greatest defenses in recent league history. That defense allowed 4.4 yards per play, coupled with 273.6 yards per game. For perspective, the Broncos are allowing 4.1 yards per play.

The Broncos completely stifled Aaron Rodgers in Sunday's win, limiting him to just 14 of 22 passing and 77 yards. It was the lowest for Rodgers in a game where he did not leave due to injury. Rodgers was also sacked thrice, to boot, and the team accounted for a total of 90 rushing yards -- just 38 of which were accounted for by Eddie Lacy.

As Packers center Corey Linsley said, via USA Today:
“They’re extremely athletic up front, they’re extremely athletic with their linebackers and secondary, so they’re able to run their twists and games and blitzes a bit faster than other people,” Linsley said.

What's the secret to shutting down one of the league's elite quarterbacks? According to Broncos safety T.J. Ward (via the same USA today piece), it's all about preparation, along with some magic.

“You’re trying to find the secret? There aren't any tricks,” safety T.J. Ward told USA TODAY Sports. "There's no secret. We're smart, we study, we know what routes are coming based on formations. It's just magic, that's what it is.”

The Patriots and Broncos Sunday Night Football matchup in Week 12 is a lot more than a Brady-Manning matchup -- it's a battle between one of the game's top offenses vs. the game's best defense. The Pats have outclassed most of the defenses that they've played this season, but facing off against the Broncos will be arguably their toughest challenge of the season.  

Follow Rob Riches on Twitter @Riches61