As the NFL enters the quarter point of the season, only three teams can boast a perfect 3-0 record: Arizona, Atlanta and Houston. Since realignment in 2002, that is tied for the fewest undefeated clubs through the first three games.

"The 3-0 start doesn't really mean anything to me other than we have another game next week," says Cardinals head coach KEN WHISENHUNT. "That's the focus that we have to have. We've stayed consistent in our approach and that's paid off for us. That's our challenge going forward. I think that we have the guys to do it."

While a strong start to the season is a good thing -- 75.7 percent of teams (84 of 111) that started 3-0 since 1990 made the playoffs -- it is hardly a guarantee of future success. There is still a lot of football left to be played.

"Our guys have a good understanding that we have to get better each and every week," says Falcons head coach MIKE SMITH. "We want to continue to build on what we've done. We have a good foundation in place the first three weeks, but that's just the first three weeks. We've got to be ready to handle adversity when adversity comes."

A look at the three remaining unbeaten clubs:

Arizona Cardinals

The Cardinals are 3-0 for the first time since 1974. Dating back to last season, the club has won 10 of its past 12 games, the best mark in the NFL.

"This is new territory for everybody on this team," says wide receiver LARRY FITZGERALD, who last week became the youngest player in NFL history to reach 700 career receptions. "Nobody on this team was born in 1974, so it's a good feeling and we want to just keep this rolling."

Through the first three weeks of the season, a league-record 248 touchdowns have been scored. However, the Cardinals, led by second-year defensive coordinator RAY HORTON, have allowed just two TDs, the fewest in the league.

"That defense is for real," says NFL Network analyst MICHAEL LOMBARDI about the Cardinals. "That defense is tough. What Ken Whisenhunt has done with this football team, he could win Coach of the Year after three games. He's played to the strength of his football team."

Arizona has allowed only 40 points this season -- 13.3 points per game -- and is the only team in the league to hold each opponent to fewer than 20 points.

"Their strength is on defense and they are as advertised," says NFL Network analyst BRIAN BILLICK. "They are physical and they are talented."

Atlanta Falcons

The Falcons have started 3-0 for the first time since 2004 and only the fourth time in franchise history (1981, 1986, 2004).

"The Falcons have gone out there and handled their business," says NFL Network analyst JAMIE DUKES. "They have two quality road wins already. (Defensive coordinator) MIKE NOLAN has been the key catalyst for this team. While (quarterback) MATT RYAN has taken that next step, it's really what that defense is doing that is setting them over the top."

Ryan leads the league with a 114.0 passer rating, completing 77 of 107 passes (72.0 percent) for 793 yards with eight touchdowns and one interception. In his career, the Falcons are 26-0 when he has a 100.0+ passer rating.

Defensively, the Falcons are one of only four teams that has not allowed 50 points yet this season (48; 16.0 points per game). Last week, in Atlanta's 27-3 victory, the Falcons held the Chargers without a touchdown, snapping San Diego's streak of 151 consecutive regular-season games with a touchdown, the second longest in NFL history. Atlanta has forced a league-high 11 turnovers and top the NFL with a +10 turnover differential.

"They've made a statement," says NBC analyst TONY DUNGY. "The defense is playing great and Matt Ryan has outplayed (Denver's) Peyton Manning and (San Diego's) Philip Rivers in six days."

Houston Texans

The Texans are 3-0 for the first time in franchise history. After winning the team's first-ever division title and playoff game in 2011, Houston has set bigger goals in 2012.

"When you look at this team on paper, and then what they put out on the field, they are the best all-around team," says NFL Network analyst and former running back LA DAINIAN TOMLINSON. "They've got talent at the skill positions with (wide receiver) ANDRE JOHNSON, (running backs) ARIAN FOSTER and BEN TATE and (quarterback) MATT SCHAUB. And (defensive coordinator) WADE PHILLIPS has this defense playing unbelievably well. They're aggressive and they really get after you."

Schaub is third in the AFC with a 102.4 passer rating and Foster ties for the NFL lead with four total touchdowns (three rushing, one receiving).

Defensively, the Texans have allowed an AFC-low four total touchdowns and 42 points (14.0 per game). Houston is allowing just 255.7 total yards per game, the best mark in the AFC and the second-best in the NFL.

"(Owner) BOB MC NAIR should be excited," says Dungy. "He's got a great offense, but they've also got a great defense."

The Cardinals, Falcons and Texans all rank amongst the leaders in fewest points allowed this season. Arizona is second (40 points), Houston is third (42) and Atlanta is fourth (48).

The three undefeated teams also rank amongst the leaders in fewest touchdowns allowed in 2012. Arizona leads the league (two), Houston is tied for second (four) and Atlanta is tied for sixth (six).

Arizona, Atlanta and Houston will all attempt to reach 4-0 this weekend. The last time each club started a season with four consecutive wins:

Arizona in 1974 started 7-0; Finished 10-4; Won division and advanced to Divisional Playoff.

Atlanta in 2004 started 4-0; Finished 11-5; Won division and advanced to NFC Championship Game.

Houston has never started 4-0 in franchise history. Joined NFL in 2002.

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