By Dean Michaels

Through the first five weeks of the 2011 NFL season, all eight divisions have at least one new team either in first place or tied for the top spot. If that holds, it will be the most new division winners in a single season.

"It's all about football around here," says quarterback ALEX SMITH of the NFC West leading 49ers. "The focus is on details. The focus is on football. The focus is on teaching. Players are executing and we're getting better every day. There's no secret. We just want to continue to take steps every single day and so far we've done that."

Entering Week 6, there are 18 teams with a .500 or better record. That's two behind the most such teams (20) through the first five weeks of a season in NFL history (2001, 2010).

"We're giving ourselves a tremendous opportunity," says Bills running back FRED JACKSON about the team's 4-1 start. "But that's all it is. It's still early. We still have a lot of work to do to get where we want to be. We're happy where we are right now, but we're not going to settle. We still have a lot of work to do and a lot of teams left to play."

Nine teams -- Detroit (5-0), Green Bay (5-0), Buffalo (4-1), New England (4-1), New Orleans (4-1), San Diego (4-1), San Francisco (4-1), Baltimore (3-1) and Washington (3-1) -- lead the way with one loss or none.

"We're just taking it one game at a time," says Packers defensive tackle B.J. RAJI. "We think of it as a one-game season every week. We just want to go out there and handle our business. And it's worked for us so far."

There is still a lot of season left to be played. And in the NFL, the only thing predictable is the unpredictability.

Of the 18 teams with a .500 or better record, half of them (nine) won six games or fewer a year ago. Those nine clubs, who have a combined 29-13 (.690) record this season, finished 2010 with a 49-95 (.340) mark.

"What we went through last year, nobody wanted to go through again," says Bills head coach CHAN GAILEY, whose team has already matched last season's win total (four). "We learned we could play in the big ball games and we were right there last year. We've learned this year how to find ways to win games in the clutch."

Comebacks continue to be a trend in 2011.

Last week, the Kansas City Chiefs overcame a 24-7 deficit to defeat Indianapolis 28-24. It marked the seventh time this season that a team trailed by at least 17 points and came back to win the game. That is the most through the first five weeks of any season in NFL history.

In addition to the Chiefs' victory, the Packers (14 points) erased a double-digit deficit to win at Atlanta. A total of 18 teams have come back from a deficit of at least 10 points to win a game this year, the most ever through the first five weeks.

A look at some of the key games in Week 6:

SAN FRANCISCO 49ERS (4-1) at DETROIT LIONS (5-0)

What a difference a year makes.

The 49ers and Lions enter this week's contest with a combined record of 9-1. Through Week 5 of last season, the teams had a total of one win and a 1-9 mark. This year, San Francisco leads the NFC West and Detroit ties for the top spot in the NFC North.

San Francisco improved to 4-1 last week with a 48-3 win over Tampa Bay. The 45-point margin of victory was the most by the 49ers since Super Bowl XXIV, when the club defeated Denver 55-10. Quarterback ALEX SMITH, who ranks second in the NFC with a 104.1 passer rating, threw three touchdown passes and posted a 127.2 passer rating; in his career as a starter, the 49ers are 8-0 when Smith has a rating of at least 100.

"Everybody is on the same page," says San Francisco running back FRANK GORE, who rushed for 125 yards and a touchdown against the Buccaneers. "Alex is playing great ball. As long as we just keep working and take it one game at a time, and continue to get better every day on the practice field, I feel like we can do whatever we want to do."

The Lions are 5-0 for the first time since 1956.

Detroit knocked off Chicago on MNF 24-13. The victory marked the third consecutive game that the Lions trailed at halftime but rallied to win. Wide receiver CALVIN JOHNSON had 130 yards and a touchdown to become the first player in NFL history with nine receiving touchdowns in a team's first five games of a season.

"We've got a big game on Sunday and we've got to try and do it again," says quarterback MATTHEW STAFFORD, who ranks third in the NFL with 13 touchdown passes. "That's the way this league is. There are 16 games and we've only played five. We've got to keep grinding and get back to work. We've got a tough team in San Francisco coming in."

BUFFALO BILLS (4-1) at NEW YORK GIANTS (3-2)

The Bills knocked off Philadelphia last week to improve to 4-1 and equal the team's win total from 2010. Buffalo forced five turnovers (four interceptions, one fumble) and leads the NFL with 16 takeaways and a +11 turnover differential.

"One of the things we've done a tremendous job with this year is winning in different fashions," says Bill running back FRED JACKSON, who ranks third in the NFL with 712 scrimmage yards (480 rushing, 232 receiving). "We've made plays on defense to win games, we've made plays on offense and we've made plays on special teams. As long as we continue to make plays like that as a team, we're going to be hard to beat. The number one thing we're trying to focus on is to get team wins."

The Giants enter the contest at 3-2 and look to get back on track after a loss in Week 5.

Quarterback ELI MANNING passed for a career-high 420 yards last week and wide receiver VICTOR CRUZ had a career-best 161 receiving yards.

"We are confident," says Manning, who ranks third in the NFC with a 102.3 passer rating. "We are doing a lot of good things but we just have to keep working. Everybody had a great study from this tape and we will come back and have a great week of practice."

HOUSTON TEXANS (3-2) at BALTIMORE RAVENS (3-1)

Two teams with at least a share of first place in its division will meet in Baltimore. The Texans enter tied with Tennessee for first place in the AFC South while the Ravens lead the AFC North.

Houston ranks third in the AFC averaging 132.8 rushing yards per game and the Texans are the only team in the NFL with two running backs with at least 250 rushing yards (BEN TATE, 321 yards & ARIAN FOSTER, 256). However, Houston will be tested on Sunday as it faces the AFC's top ranked rushing defense in Baltimore (72.5 yards per game).

"This is the NFL," says Texans linebacker BRIAN CUSHING, "and every week is going to be a fight. The great teams find a way to win. We're going to play a great team at their place this week. It will definitely be a test."

The Ravens were off last week and have had success in games following a bye, notching a 3-0 record under JOHN HARBAUGH and winning eight of their past nine.

NEW ORLEANS SAINTS (4-1) at TAMPA BAY BUCCANEERS (3-2)

First place in the NFC South will be on the line when the 4-1 Saints visit the 3-2 Buccaneers. The teams have split the season series each of the past three years and the road team has won four meetings in a row.

The Saints won their fourth game in a row with a 30-27 win over the Carolina Panthers.

Quarterback DREW BREES completed 32 of 45 passes (71.1 percent) for 359 yards and two touchdowns to lead the Saints. He now has thrown a TD pass in 32 consecutive games -- equivalent to two full regular seasons -- and that is the third-longest streak in NFL history. He also extended his NFL-record streak of consecutive games with at least 20 completions to 25 games in a row. Brees has passed for at least 350 yards in each of the past three contests and can become the first player in NFL history with 350+ passing yards in four consecutive games.

"We're going to get a Tampa Bay team that's hungry," says New Orleans head coach SEAN PAYTON. "When you play a team that comes off a tough game like they are, you understand that they're going to be focused and ready to get past it."

Tampa Bay is seeking its third consecutive win at home and looks to rebound after a Week 5 loss at San Francisco.

"This is the National Football League," says Buccaneers head coach RAHEEM MORRIS. "The schedule is tough every single year and every single game. We have to embrace the fact that we get to play tough teams. That's fun football and we have to get better this week. We have to get ready to play a tough football game against the New Orleans Saints."

NFL 2011 - Unpredictability Reigns: All Divisions Have at Least One New Team in First Place