There's no doubt defense will help decide who wins Super Bowl XLVII.
As the age-old adage goes, defense wins championships. It might be a huge cliche, but it wouldn't be so big if it hadn't been proven true so many times.
This game is an intriguing matchup between a 49ers defense that was one of the NFL's best in the regular season, and a Baltimore Ravens unit that had an average regular season but has found a another level in the postseason.
In order to stop quarterbacks like Joe Flacco and Colin Kaepernick, it's going to be imperative the defenses get the job done.
With so much on the line, here's how each of the defensive units stack up.
With the 3-4 schemes both teams utilize, the defensive lines have been used mostly to defend the run rather than get after the passer. For the 49ers and Ravens, the outside linebackers are generally the ones who do a majority of the blitzing.
Haloti Ngata has done a very good job becoming more than just a space-eater, but he hasn't had a great 2012. That fact has hurt the Ravens defense as a whole.
It's a bit of a toss-up here over which unit to choose, but the 49ers get the slight edge.
A lot will hinge on what defensive tackle Justin Smith can do. A triceps injury has really hampered his effectiveness in 2012. He can be a real difference-maker Sunday if he can play at his peak level.
Edge: San Francisco 49ers
Ray Lewis is, without a doubt, a legend. He's had a great postseason to this point. Other than him, though, the linebackers simply don't stack up to what the 49ers bring.
Terrell Suggs has had the worst season of his career, albeit injury-shortened. In addition, his pass-rushing might be negated by Kaepernick's running ability.
On the other side, Aldon Smith might be the best pure pass-rusher in the league. He's had a big dry spell, though, so he might be invisible during the game. On the other hand, if Smith can get on a roll, Flacco will have a miserable time.
The combination of Patrick Willis and NaVorro Bowman might be the best inside linebacker tandem in the league. They can shut down Ray Rice and the Ravens running game.
For San Francisco, it's a case of strength in numbers.
Edge: San Francisco 49ers
The Ravens will get the edge here because of what Ed Reed and Cary Williams bring to the Ravens' secondary.
Even at 34 years old, Reed remains a huge ball hawk who can cause nightmares for opposing quarterbacks. Williams has already recorded two interceptions in the playoffs.
Winning the turnover battle will be vital in determining the outcome of Super Bowl XLVII.
Baltimore has faced three very good quarterbacks in Andrew Luck, Peyton Manning and Tom Brady. The Ravens have come up with five interceptions from that trio in this year's playoffs.
Kaepernick does bring a different dimension, but he should be wary when throwing downfield knowing how poorly Manning and Brady have done already.
Edge: Baltimore Ravens