Head coach Jim Harbaugh has the 49ers off to a 5-1 start
The San Francisco 49ers are off to a 5-1 start and lead the NFC West by two-and-a-half games over the Seattle Seahawks. The 49ers are off to their best start since 1998 and it has surprised the football world.
The 49ers are led by a stellar defense that has kept them in every game, allowing the offense multiple opportunities to get the job done. The formula has been a success so far, as Alex Smith has engineered three come-from-behind victories.
Do the 49ers have the best defense in the NFC?
Right now, the answer is a resounding "yes."
Let's take a look at five key factors as to why this defense is the best in the division.
Carlos Rogers has three interceptions thus far
In 2010, the defensive backfield was a weak link for the 49ers defense. Early in the 2011 season, it looked like much of the same. This unit allowed the Cowboys to throw the ball successfully and drive for two late scores, which beat the 49ers in the second game of the year.
However, as the season has progressed, the secondary has improved dramatically. Free-agent acquisition Carlos Rogers has provided stability to this group and is a major upgrade over Nate Clements, who he replaced. Rogers leads the 49ers with three interceptions.
When safety Dashon Goldson returned from injury, that was also a boost for the defense. Goldson missed the first two games and this unit struggled. Goldson has been very solid at one safety position.
The other safety spot is held down by former Buffalo Bill, Donte Whitner. He is a good run-stopper and has been adequate in pass coverage.
Shawntae Spencer was supposed to be the other starting cornerback, but injuries have caused him to miss too much time. He has been replaced by Tarell Brown who was, frankly, very weak early in the season. However, to his credit, Brown has been improving and I felt had his best game of the year at Detroit.
Rookie Chris Culliver is also contributing as a nickel or dime back, which is a pleasant surprise.
Patrick Willis is having an All-Pro caliber season
The San Francisco 49ers and the Green Bay Packers are tied atop the league with 14 turnovers created. The 49ers have eight interceptions and six fumble recoveries.
On the flip-side, the 49ers offense has only turned the ball over six times, resulting in a plus-eight turnover margin. This is the second best turnover margin in the league.
If you win the turnover battle, you have a much greater probability of winning the game. The fact that the 49ers have such a strong turnover margin is a key reason behind their 5-1 start.
Vic Fangio has done a tremendous job with the 49er defense
On both sides of the football, the 49ers have received a major uplift in terms of their coaching. Not to denigrate previous 49ers coaches, but this current group under Jim Harbaugh is excellent.
Defensive coordinator Vic Fangio has done an excellent job bringing the 49ers defense together. In their last two games, the 49ers have held Tampa Bay without a touchdown and also did a very good job against the high-powered, explosive Detroit Lions.
The 49ers' defensive game plans are excellent, as are Fangio's in-game and halftime adjustments. Fangio keeps the opposition off balance with a variety of schemes, and the offense never knows where the pressure is going to come from.
Against the Lions, the 49ers defense got a lot of pressure on Matthew Stafford and sacked him five times. The amazing thing about this sack total is that the 49ers didn't blitz at all during this game. However, Fangio kept the Lions off balance by sending different people from all angles, which worked very well.
The coaching of the 49ers' defensive unit has been outstanding and we can see it, as they have improved dramatically since early in the season. Fangio has complete control over the 49ers defense and he deserves a ton of credit for their improvement.
Justin Smith sacks Matthew Stafford
The 49ers' defensive front has been able to get pressure on the quarterback without resorting to excessive blitzing.
Defensive end Justin Smith is having a Pro Bowl-caliber year and also saved the game against the Eagles. He hustled downfield to strip Jeremy Maclin from behind and caused a fumble, which the Niners would recover, sealing their victory.
Opposite Smith is Ray McDonald, who has also played well this year. Rookie Aldon Smith leads the 49ers with five-and-a-half sacks, even though he is not an every down player.
The pass-rush is aided by the fact that defensive coordinator Vic Fangio will frequently send pass-rushers from alternative locations. As the 49ers pass-rush has improved, it also eases the burden on the secondary. They are not required to cover for as long, which is a huge benefit.
Bowman and Willis combine to tackle Jahvid Best
The San Francisco 49ers have an excellent front seven that is largely responsible for their outstanding defense against the run. The 49ers have not allowed a back to rush for over 100 yards in their last 28 games.
The 49ers are allowing only 74.7 yards per game on the ground, which is second in the league. Only the Cowboys are better, allowing just 69.6 yards per game.
The 49ers' defensive front seven is outstanding. NaVorro Bowman teams with Patrick Willis at the two inside linebacker positions. Bowman, who is in his second year in the league, has stepped in admirably, following the departure of Takeo Spikes via free agency.
Willis and Bowman combine speed and power to put the stop on opposing ball carriers. The other outside linebacker spots are handled by Ahmad Brooks and Parys Haralson, with Aldon Smith making a contribution with his pass-rushing skills.
Isaac Sopoaga and Ricky Jean-Francois are doing a great job controlling the middle of the field as nose tackles. With Ray McDonald and Justin Smith, the 49ers' defensive line is very strong.
Rookie Aldon Smith leads the 49ers in sacks
The San Francisco 49ers are allowing fewer points per game than any team in the NFC. Giving up only 16.2 points per game ranks them No. 2 in the entire NFL.
A key measure of defensive success is the number of points they give up. With the 49ers leading that category, I can confidently say that they have the best defense in the NFC.
An exciting aspect about this defensive success is that the 49ers are just now learning all of the nuances of Vic Fangio's defensive schemes. They are improving every week and the players believe in the coaching staff and what they're being taught to do.