Power Rankings: How do you spell unbeaten? D-E-F-E-N-S-E

Updated Sept. 30

Take a look at the top three teams in the CBSSports.com Power Rankings. The New York Giants, Tennessee Titans and Buffalo Bills are all undefeated, the only three teams without a loss.

They also have something else in common, which is why they are where they are -- it's called defense.

As much as I hate to admit it, since I am a connoisseur of offense, defense is ruling the NFL early on.

As we raced to anoint the Dallas Cowboys as the team to beat, we lost vision of their so-so defense. Buried under their high-scoring, fun-to-watch offense is the Cowboys' 20th-ranked scoring defense, which is giving up 22.2 points per game.

The top three teams in the rankings are all in the top 10 in scoring defense. The Titans are tops in the league with an average of 11.3 points allowed, followed by the Giants, who are tied for second with Baltimore at 14.3. The Bills are sixth at 15.8.

Those three are also in the top 10 in sacks, with the Titans tied for second with the Steelers at 15, the Giants have 13 in three games to tie for fourth with the Jets and the Bills have 10 to tie for 10th with three other teams.

Getting after the quarterback is a must in this NFL. The three top teams in our rankings show just how important.

Poll Which unbeaten team has the best defense? Bills Giants Titans

The Cowboys fell from the top spot to No. 5 by losing to the Washington Redskins. Washington, which has won three consecutive games, is a big mover in these rankings, jumping from 12th to fourth.

They're not like the top three teams. They are 15th in scoring defense and have just six sacks to rank tied for 23rd with three other teams.

The Redskins are making their move behind young quarterback Jason Campbell. He has developed into a capable passing threat that gives them a chance every week.

I love watching the Cowboys' offense, but even I know a 20th-ranked defense isn't good enough. If that defense doesn't improve, their perch in the top five won't last long.

The Power Rankings though Week 4:

Power Rankings
Current		Team	Previous
	1	Giants · Trends	2
	They move to the top spot without playing a game, thanks to the Cowboys losing. The Giants were the best at the end of last season and they're the best now.
	2	Titans · Trends	3
	With that defense, they will stay close to the top all season long. Kerry Collins has really helped the passing game.
	3	Bills · Trends	6
	Even when things didn't go well against the Rams, they found a way to turn it around. They're good. Trent Edwards is good.
	4	Redskins · Trends	12
	As long as Jason Campbell continues to make the strides he's making, they will get better and better. Give Jim Zorn credit for putting Week 1 behind.
	5	Cowboys · Trends	1
	Defense, guys. It's all about the defense. They give up too many big plays. You won't win a Super Bowl that way.
	6	Steelers · Trends	8
	That offense has issues. They can't keep letting Ben Roethlisberger get hit like he has been the past two weeks. With no Willie Parker or Rashard Mendenhall, it will be tough to get the running game going.
	7	Panthers · Trends	10
	The best thing about the first month has to be that Jake Delhomme hasn't had many problems in coming back from elbow surgery. The defense is coming off a nice game against Atlanta.
	8	Buccaneers · Trends	11
	They're 3-1, but they have big-time quarterback issues. When will they ever throw the ball down the field? The horizontal passing game is tough to watch.
	9	Broncos · Trends	4
	Here's another team that has defensive issues. When will they stop somebody? All that offense is going to waste.
	10	Patriots · Trends	13
	They've had time to stew about their upset loss to the Dolphins. Now they get back to work. Wonder how warm and fuzzy Bill Belichick will be.
	11	Packers · Trends	7
	Two consecutive losses have some wishing they had Brett Favre back. Hey, it's a long season. Let it play out.
	12	Ravens · Trends	9
	They squandered a good chance to get to 3-0 on Monday night. At some point they have to turn Joe Flacco loose. They will waste a lot of good defensive efforts if they don't.
	13	Bears · Trends	21
	If Kyle Orton can continue to grow they just might win that division. The pass defense had issues against the Eagles, which might be a concern down the road.
	14	Eagles · Trends	5
	They are now the fourth team in a four-team division. That doesn't mean they're done. They're still capable of winning the NFC East. They certainly need Brian Westbrook back on the field.
	15	Jaguars · Trends	15
	Their defense, which was supposed to be a strong point, isn't anymore. They can't stop the pass. That's an issue every week.
	16	Chargers · Trends	17
	Winning two consecutive games has the Chargers feeling good again. They did make it interesting against the Raiders.
	17	Saints · Trends	20
	They will be a joy to watch all season long with the way Drew Brees is playing. The defense tightened up against the 49ers, which is a good sign for the rest of the way.
	18	Colts · Trends	16
	If ever a team needed a week off it was the Colts. They have so many injured players that it came at the right time.
	19	Jets · Trends	24
	With six touchdown passes last week, Brett Favre now has 12 on the season. The Jets have to be happy about being .500.
	20	Cardinals · Trends	14
	Are they the same old Cardinals? It sure looked that way in the first half against the Jets. They return home for the first time in three weeks Sunday. They need it.
	21	Seahawks · Trends	22
	Want ad: Receivers needed. Apply with Seattle Seahawks. OK, it's not that bad -- but it's close. They need to get people healthy.
	22	49ers · Trends	18
	J.T. O'Sullivan might leave in a body bag if they don't protect him better. He's getting killed.
	23	Falcons · Trends	19
	After the first month they're 2-2. They'll take it. They do need to run it better than they did last Sunday -- or else.
	24	Vikings · Trends	23
	Changing from Tarvaris Jackson to Gus Frerotte has produced a 1-1 record. We'll see how it is for the long run.
	25	Dolphins · Trends	25
	It's too bad they had the week off after their upset of the Patriots. It will be interesting to see if the momentum carries over to this week.
	26	Browns · Trends	29
	They got a victory against the Bengals, but they still can't do much on offense. It's Brady Quinn time. Now.
	27	Texans · Trends	26
	The good news for the Texans is that Matt Schaub bounced back. The worry is that the defense isn't playing all that well.
	28	Raiders · Trends	27
	Does it really matter who coaches this team with Al Davis looking down from his perch? Fire them all. As long as he's still running things, it won't matter.
	29	Chiefs · Trends	31
	Give it to Larry Johnson and you have a chance. Of course, you don't get to play the Broncos defense every week.
	30	Bengals · Trends	28
	At 0-4, it's time Marvin Lewis felt the heat. How does he not? If last Sunday showed anything, it's that they have no chance without Carson Palmer.
	31	Lions · Trends	30
	So the Lions finally fired Matt Millen. It's too bad his stink is still left behind. Bad drafts will kill a franchise.
	32	Rams · Trends	32
	They've given up 30 points or more in four consecutive games. Yecch. Even though Jim Haslett was the defensive coordinator, he will get this team playing better.