Pitting two of the NFL’s five remaining perfect squads in primetime, the 6-0 Denver Broncos play host to the 6-0 Green Bay Packers in Week 8’s potentially season-altering matchup at Sports Authority Field at Mile High on “Sunday Night Football.”

Joining New England, Carolina, and Cincinnati, the Packers and Broncos have thus far gone unscathed and enter the game with comfortable leads in the NFC North and AFC West, respectively.

Peyton Manning is on pace for one of the worst seasons of his career and the Broncos are forced to uncharacteristically rely on their defense to win games. The 39-year-old has maintained his focus on practice this week with the Packers expected to give the Broncos their toughest test.

"We want to have a good week of practice, play well and try to get a win — try to get a win against a really good team and a hot team," Manning told the Denver Post. "That's where my focus is, and I think that's where the team's focus is."

Denver enters the high-profile matchup as a 2.5-point underdog in their home stadium. The ungenerous, but narrow, betting line may have something to do with who Denver’s beaten so far this season. The Broncos are off to their best start since 2013, but only one of their six victories have come against teams that are currently .500 or better; a 16-10 slugfest at rival Oakland that saw Manning chuck two interceptions without a touchdown pass and required a 74-yard interception return for a score by cornerback Chris Harris with less than seven minutes remaining.

However, the same could be said for quarterback Aaron Rodgers and the Packers, whose Week-5 24-10 victory over now 3-3 St. Louis stands as their only win over a .500 or better squad.

Still a loss for the Broncos, given their upcoming schedule, could prove detrimental later this season. Denver travels to Indianapolis for Week 9, followed by an AFC West showdown with Kansas City and a trip to Chicago, and then a visit from New England in Week 12.

The Packers get another shot at an undefeated squad next week as well, when they head to Carolina. But they will face lesser NFC North foes like 1-6 Detroit twice over the subsequent four weeks.

Before perhaps the biggest game of Week 8, here are three key storylines to watch and monitor before and during Sunday night’s matchup.

Manning vs. NFL’s No. 9 Pass Defense

Currently accounting for 1,524 passing yards and seven touchdowns, and tied for the league-worst with 10 interceptions, Manning’s on pace for his worst total output since 2008. He’s lofted up seven of those picks compared to only two touchdowns in Denver’s last three games, and next draws the Packers ninth-ranked pass defense.

Green Bay, led by veteran corner Sam Shields and rookie corner Damarious Randall’s 15 combined passes defensed, is surrendering 237 passing yards per game and has allowed only seven total touchdowns. Furthermore, opposing passers are notching a 73.4 rating while staring down the Packers No. 3 pass rush, which has accounted for 23 sacks.

Still, Randall (ankle) as well as starting safety Morgan Burnett (calf) made their way to the team’s official injury report this week and their status for the game is presently unclear.

The same could be said, only worse, for Rodgers if not for his youth and elusiveness in the pocket. Denver’s defense is first in the league with 26 sacks, 192 passing yards per game, and third in opposing passer rating 69.6. Dealing with injuries on the offensive line and in his receiving corps, Rodgers has taken 11 sacks in six games but he’s still fired off 15 touchdowns to two interceptions and he’s third on the team with 160 rushing yards off 29 attempts.

Does Eddie Lacy Finally Breakout?

Rodgers deserves even more credit for playing under duress when you consider the poor start to third-year running back Eddie Lacy’s season. After gaining more than 1,100 yards and scoring 20 total touchdowns in his first two seasons, the 25-year-old Lacy has dealt with a nagging right ankle injury for most of the season and has gained a mere 260 yards and one touchdown off 67 attempts in six games.

Lacy sat out all but one series in Week 6’s 27-20 win over San Diego due to the injury, and up until now the Packers have relied on veteran James Starks to handle the extra workload. Despite Lacy’s troubles, Rodgers and Starks have helped Green Bay post the league’s No. 8 rushing attack.

However, the bye week didn’t afford Starks any healing powers and he’s dealt with a hip injury since the San Diego victory. And the Packers don’t have much depth after Starks, with rookie Alonzo Harris next up on the depth chart followed by fullback John Kuhn and rookie Aaron Ripkowski.

Should Starks sit out, Lacy will have to re-emerge against the Broncos No. 3 rushing defense, a unit allowing just 3.6 yards per carry and 89.2 yards per game.

Will Denver’s D Come Back To Earth?

To put it bluntly, the Broncos have played perfect defense. In every major statistical category (points, yards, downs, takeaways, etc.) they are either first or somewhere in the top three. The only exceptions being sixth with 195 kickoff yards and 20th with 141 punt return yards allowed this season.

But as mentioned before, Denver hasn’t faced a team of Green Bay’s caliber, or a quarterback like Rodgers this season.

It’s very possible the other shoe drops for the Broncos this week unless Manning and the offense can exploit the Packers most glaring weakness: stopping the run.

For all of Green Bay’s perceived invincibility, especially on offense and against the pass, the defense is still susceptible to a good power running game. The Packers are No. 22 in the league with 118.5 rushing yards allowed per game, which could mean a big game from Denver running back Ronnie Hillman.

The fourth-year back has fought off C.J. Anderson and Juwan Thompson for the starting role this season, and he’s ripped off 235 of his 323 yards in the last three games, specifically barreling over Cleveland’s league-worst effort against the run and Minnesota’s No. 14 ranked unit.