ESPN's Joe Theismann answers five key questions on Week 5 of the NFL season:

Can other teams learn from the way the New York Giants' defense stopped the St. Louis Rams?
Other teams can learn from what the Giants did, but their problem is not having players like Michael Strahan or Keith Hamilton. The Giants' biggest factor was the rush from their defensive line, particularly Strahan, who had four sacks. The Giants basically rushed four players and dropped seven into coverage.

There was no question which team -- the Giants -- was the better team Sunday. But the team that played the best did not win. The Giants made a critical mistake at the end of the game on Joe Jurevicius' fumble, and it cost them. The way the linebackers and the secondary played, however, the Giants are for real. Now they face a great NFC East showdown with Philadelphia at the Meadowlands.

I still feel the Giants are the team to beat in the NFC, especially with the Rams missing Marshall Faulk for up to four weeks. Mike Martz drafted Trung Canidate in case something happened to Faulk, the league's MVP, and now we get a chance to see if Martz's selection will pay off.

The Rams showed some vulnerability against the Giants. I liken the Rams' offense to the Colts' offense in that they are both built on making big plays. If Kurt Warner or Peyton Manning have to throw seven or eight times during a drive instead of two or three times, the chances of something bad happening increase. And that's what happened to Warner against the Giants and Manning against the Raiders.

Should the Seattle Seahawks be considered a playoff contender?
In the preseason I picked Seattle to be the league's surprise team. So yes, the Seahawks are playoff contenders. People also thought Denver was good enough to go the Super Bowl, but the Seahawks dismantled them. I don't know if it's Seattle being good or Denver starting to see the effects of missing Ed McCaffrey.

How about Trent Dilfer? Nobody wanted him in the offseason. The Ravens didn't want him even though he was 11-1 as the starter a year ago. The Redskins wouldn't sign him because they felt he would be liked too much in the locker room. Then he goes to Seattle, willing to be a backup to Matt Hasselbeck, who has struggled miserably. Now, after two straight wins, Dilfer is 13-1 as a starter over the last two years.

I look at Dilfer the way most people used to look at Cris Carter. When Buddy Ryan got rid of Carter in Philadelphia, he said, "All he does is catch touchdowns." Well, all Dilfer does is win football games. Nothing wrong with that.

What's up with the Miami Dolphins and the second half of games against the New York Jets?
I believe home-field advantage matters more in the NFL than any other sport. In baseball, hockey and basketball, those athletes play so many road games that I think they can become oblivious to opposing stadiums. In the NFL, teams get only eight chances to play in a different city, unless they make the playoffs.

The crowd makes it difficult to communicate. And the Jets fans at the Meadowlands certainly get loud. Once things start going badly for a road team, it almost becomes contagious. Much like the Colts' problems against New England in Foxboro, the Dolphins, for some reason, struggle in New York. But I still think Miami is the team to beat in the AFC East.

Are the Green Bay Packers legitimate Super Bowl contenders in the NFC?
As long as Brett Favre is the quarterback, they have to be considered a viable threat to win every game they play. If Favre has a bad game, they won't win. If Favre is magical, the Packers will win.

The Packers have upgraded their defense into one of the league's best units; statistically, they rank third in the NFL. Against Baltimore, you had to watch the game to know how poorly the Ravens' offense played. They dropped passes, Elvis Grbac threw interceptions at crucial times. The Packers dropped other opportunities for interceptions.

Football games have only five or six big plays in them. With so much parity in the league, a defensive back has to make a play when he has the oppotunity. The same thing goes for offense, when receivers have a chance to make big plays. For the Packers, Bill Schroeder has stepped up, Antonio Freeman looks rejuvenated, Ahman Green is running hard, and Dorsey Levens is getting back into the mix. The Packers have an explosive offense that unloaded on one of the league's best defenses.

Why is Peyton Manning throwing so many interceptions?
Manning has had nine interceptions in four games, and four of them have been run back for touchdowns. Any time a quarterback is throwing interceptions, the defense deserves some credit for being in the right place.

On Sunday night, Manning's first interception was a miscommunication between Manning and tight end Marcus Pollard. Pollard went one way, and Manning's throw went the other, and the Raiders' Anthony Dorsett returned it for a touchdown. In man-to-man coverage, that will happen. The second one, to Tory James with 1:20 to go, was just a bad throw.

Manning's interceptions aren't attributed to his inability to read the coverages. Two weeks ago, he had a few bad bounces against New England. At the same time, he is not throwing with the same efficiency we have seen before.

Manning's real strength lies in play-action passing. When the running game is struggling, it's hard to play-action pass. But why is it happening? I guarantee you it's a question he'll be asking himself in the coming days.

A game analyst for ESPN's Sunday Night Football, former NFL QB Joe Theismann won a Super Bowl and a league MVP award. He reviews the NFL each week for ESPN.com in Cup o' Joe.