The NFL Live crew debates whether Buffalo's 3-1 start means the Bills will be around for the playoffs or whether they'll fall off. (1:18)

Defense wins championships. So how's yours looking through the first quarter of the season?

Here's a rundown of our Week 5 Power Rankings as determined by ESPN's power panel -- a group of more than 80 writers, editors and TV personalities -- with a special focus on all 32 units.

ESPN Stats & Information's John McTigue contributed the following information.

Methodology: These rankings reflect which teams voters think would win head-to-head matchups. Higher-ranked teams would be favored against lower-ranked teams. Coming off a win doesn't guarantee a jump, and a loss doesn't guarantee a fall.

Previous rankings: Week 4 | Week 3 | Week 2 | Preseason

2017 record: 4-0

Week 4 ranking: No. 2

Kirk Cousins completed just 58 percent of his passes against the Chiefs on Monday night ... which was still the best by any quarterback against them this season. Kansas City has allowed a league-best 51 completion percentage en route to a 4-0 start.

2017 record: 3-1

Week 4 ranking: No. 4

Injuries have been an issue in Green Bay, but the pass rush has churned no matter who has been in it. The Packers have generated pressure at the fourth-highest rate this season -- on 31 percent of dropbacks -- even with injuries to Mike Daniels, Ahmad Brooks and Nick Perry.

2017 record: 3-1

Week 4 ranking: No. 1

The defense forced two takeaways against Aaron Rodgers but failed to force any against Mike Glennon, Matthew Stafford or Tyrod Taylor. The offense has committed six turnovers the past two games, so if the defense can't force any themselves, Atlanta will be facing an uphill battle.

2017 record: 3-1

Week 4 ranking: No. 5

The Broncos' rushing defense has allowed 2.4 yards per rush and 50.8 rushing yards per game through the first four weeks -- and that was done against backs such as Ezekiel Elliott, LeSean McCoy, Marshawn Lynch and Melvin Gordon (among others). Defense has won Denver a title before, and if it keeps this up, it might be able to do it again.

2017 record: 3-1

Week 4 ranking: No. 6

The offense was supposed to make all the headlines, but the Steelers have quietly allowed the second-fewest points per game (14.8) this season. It might not be the "Steel Curtain," but it has led to a 3-1 record and first place in the AFC North.

2017 record: 2-2

Week 4 ranking: No. 12

Aside from a hiccup against the Titans in Week 3, the Seattle defense has held opponents to 18 or fewer points three times so far this season. The Seahawks are 45-7-1 (.858) when holding opponents fewer than 20 points during the Russell Wilson era, which is the most such games in that time.

2017 record: 2-2

Week 4 ranking: No. 3

It's a great advantage having Tom Brady, but it's not so great when your defense turns opponents into Tom Brady. The Patriots' defense has allowed a higher completion percentage, more passing touchdowns and more yards per attempt than Brady has thrown this season.

2017 record: 3-1

Week 4 ranking: No. 13

The Eagles have allowed the fewest points in the first three quarters of games this season but have allowed the second-most in fourth quarters. Philadelphia has three wins, but the past two were by a combined five points. If the Eagles can tighten up in the fourth quarter, they could start winning more comfortably.

2017 record: 3-1

Week 4 ranking: No. 8

The best offense is sometimes a good defense. The Lions are tied for the league lead with 11 takeaways, which has led to 47 points off turnovers. Last season, Detroit had 14 takeaways, leading to only 28 points off turnovers.

2017 record: 2-2

Week 4 ranking: No. 17

J.J. Watt doesn't even have a sack this season, but it hasn't mattered much for Houston thanks to rookie quarterback Deshaun Watson and a still-potent defense. They struggled to stop Tom Brady -- who hasn't? -- but in all other games, they've allowed just one passing touchdown with four picks.

2017 record: 2-2

Week 4 ranking: No. 7

The Raiders are bending this season, but the defense has yet to really break. Oakland has held opponents to just three touchdowns on 12 red zone trips through four weeks, the lowest touchdown percentage allowed in the red zone so far in 2017.

2017 record: 2-2

Week 4 ranking: No. 9

DeMarcus Lawrence has been a force so far this season with an NFL-leading 7.5 sacks. Unfortunately for Dallas, no other defensive player has been nearly as disruptive; the rest of the team has combined for just 4.5 sacks and two picks.

2017 record: 3-1

Week 4 ranking: No. 22

There's no place like home. The 37-year-old Julius Peppers, a North Carolina native, is playing like he's 27 with a team-leading 4.5 sacks through four games. Opponents are still completing 71 percent of their passes against Carolina, but Peppers is at least knocking them back a bit.

2017 record: 2-2

Week 4 ranking: No. 14

The Redskins entered Week 4 with the third-best opponent Total QBR. Alex Smith's big Monday night knocked Washington down a few pegs, but Josh Norman's injury could knock them down even further if he ends up out for an extended period.

2017 record: 3-1

Week 4 ranking: No. 15

One. That's how many passing touchdowns the Bills have allowed through four games. It's no wonder Buffalo has allowed the fewest points per game and currently owns sole possession of first place in the AFC East.

2017 record: 3-1

Week 4 ranking: No. 16

If you think Todd Gurley is off to a great start, then you should see what opposing running backs have done against Los Angeles. The Rams have allowed 4.9 yards per rush and a league-worst seven rushing touchdowns so far this season. They'll have to shore up the rushing defense if they have want to contend.

2017 record: 2-2

Week 4 ranking: No. 11

Sam Bradford and Dalvin Cook are hurt, which means the Minnesota offense might not be as explosive moving forward, but the defense is still intact. The Vikings are allowing 19.0 points per game this season and 19.8 since 2014, sixth best in that time.

2017 record: 2-1

Week 4 ranking: No. 19

The Buccaneers might have cause for concern considering their defense has just one sack through three games. Perhaps even more concerning is the pass rush has generated pressure on just 16 percent of dropbacks, the worst in the NFL. This probably won't bode well against Tom Brady and the Patriots on Thursday night.

2017 record: 2-2

Week 4 ranking: No. 10

Pass defense was one of the Titans' biggest weaknesses last season, and it doesn't appear much has changed in 2017. Tennessee has allowed 11 passing touchdowns this season, tied for most in the NFL, including eight in the past two games. If Marcus Mariota's injury is serious, the burden will fall even more on the defense for Tennessee to compete.

2017 record: 2-2

Week 4 ranking: No. 24

The Saints entered Week 4 with the second-worst defense, according to FPI, and then pitched their first shutout since 2012. FPI isn't buying into the one-off performance, though, as it only slightly improved New Orleans to the fourth-worst defense.

2017 record: 2-2

Week 4 ranking: No. 21

The Cardinals allowed Total QBRs of 75 or better to Matthew Stafford and Dak Prescott, and QBRs of 25 or worse to Jacoby Brissett and Brian Hoyer. In other words, they've struggled against the good and thrived against the not-so-good. Carson Wentz, Jameis Winston and Jared Goff are up next for Arizona.

2017 record: 2-2

Week 4 ranking: No. 18

After recording eight interceptions and eight sacks between the first two games of the season, the Ravens have recorded just one pick and one sack in the two games since. With the offense sputtering, Baltimore will need the defense to be as disruptive as possible.

2017 record: 1-3

Week 4 ranking: No. 25

Cincinnati's three-loss start can't be blamed on its defense. The Bengals have allowed 16.8 points per game through four weeks, the third best in the NFL. The problem is the offense has scored a paltry 16.0 points per game.

2017 record: 2-2

Week 4 ranking: No. 20

The Jaguars have shown flashes of good and bad this season, and the defense is no exception. The pass rush has generated a league-best 18 sacks through four weeks, but the rushing defense has allowed a league-worst 5.7 yards per rush.

2017 record: 0-4

Week 4 ranking: No. 27

Tackling has been an issue for the Chargers' defense so far in 2017. It has allowed 2.6 yards per rush after first contact, the worst in the NFL. To put it in perspective, the Broncos have allowed 2.4 yards per rush overall.

2017 record: 2-2

Week 4 ranking: No. 31

Raiders quarterback Derek Carr lit up the Jets with an 82 completion percentage in Week 2 with three touchdowns and no picks. All other quarterbacks who have played the Jets this season? Four touchdowns, four picks and a 53 completion percentage. New York is already halfway to matching its interception total from 2016.

2017 record: 1-2

Week 4 ranking: No. 26

Jay Cutler is struggling, but so is the pass defense. The Dolphins have allowed opponents to complete 76 percent of their passes, the worst in the NFL. Miami is also one of four teams without a pick this season.

2017 record: 1-3

Week 4 ranking: No. 23

Mitchell Trubisky will make his NFL debut on Monday Night Football against the Vikings, and if he wants to win, he'll have to put a bunch of points on the board. FPI has the Bears with the fifth-worst defense so far this season.

2017 record: 0-4

Week 4 ranking: No. 29

The 49ers are building for the future. The good news is all the young pass-rushers San Francisco has drafted appear to be paying off. The Niners are pressuring quarterbacks at the sixth-highest rate through four weeks. They did so at the fifth-lowest rate last season. Progress.

2017 record: 0-4

Week 4 ranking: No. 28

The blame for the Giants' start should extend well past the offensive struggles. The defense has faced the most passes (129) without an interception this season and has generated just two takeaways, tied for second fewest in the NFL.

2017 record: 1-3

Week 4 ranking: No. 30

The Colts have allowed the most points so far. But to the defense's credit, the offense was on the field for four of the 16 touchdowns allowed. Take those out, and the Colts' defense has allowed the fourth-most points.

2017 record: 0-4

Week 4 ranking: No. 32

Maybe when first overall pick Myles Garrett takes the field, things will improve for the defense. But for now, the Browns rank 31st in defensive FPI and last in opponent QBR. Hang in there, Cleveland.