There's an old saying in the National Football League that "defense wins championships."
Sure, quarterbacks may get all the glory and offense may generate the plays that get the majority of "oohs" and "aahs," but it's the teams that make the big plays on defense that more often than not end up hoisting the Lombardi trophy when all is said and done.
Both the Ravens and 49ers boast defenses led by phenomenal linebackers in Baltimore's Ray Lewis and San Francisco's Patrick Willis, but it's how those teams perform as a unit on defense that will determine who emerges from Super Bowl XLVII with the victory.
So, what is the one thing that each defense must do in order to win the game?
San Francisco 49ers: Keep the Ball in Front of You
The San Francisco 49ers were able to overcome a 17-point first-half deficit against the Atlanta Falcons in the NFC Championship Game, but it's certainly advisable that the team not tempt fate by letting themselves get in a hole quickly.
That hole against Atlanta was borne of the Falcons attacking San Francisco's defense vertically, an area in which the Ravens have had great success during their run to New Orleans.
That makes it incredibly important that the 49ers not have the sorts of defensive lapses that led to Atlanta's first touchdown in the NFC title game.
There were actually not one but two tactical missteps by the 49ers secondary on Matt Ryan's first-quarter scoring strike to wide receiver Julio Jones.
First cornerback Tarell Brown, apparently believing that Jones is going to break the route off, hands off coverage to free safety Dashon Goldson.
Then Goldson, either because he too thinks Jones is going to break the route or just falls asleep at the switch, lets Jones get behind him, and with strong safety Donte Whitner much too far away to be of any assistance, the result is an easy score.
No team in the playoffs has been more aggressive in attacking secondaries down the field this year than the Ravens, so the 49ers need to be mindful of their coverages and leave the safeties back to help over the top.
Luckily for the 49ers, they also possess the best linebacking corps in the NFL, and the quartet of Aldon Smith, Ahmad Brooks, Navorro Bowman and Willis should be able to hold their own against the run without the safeties cheating up into the box.
Baltimore Ravens: Slow Down the Read-Option
Welcome to easier said than done theater.
The read-option has taken the National Football League by storm this season, and since the insertion of quarterback Colin Kaepernick into the starting lineup, the San Francisco 49ers have run that offense as well as anyone.
That includes in the playoffs, where Kaepernick and the 49ers have demonstrated just how difficult it can be to slow down the "option" part of this offense.
Against the Green Bay Packers in the Divisional Round, Kaepernick gashed the Packers for an NFL-record 181 yards, due in large part to the huge holes that were afforded him by Green Bay's attempts to stop Frank Gore.
In the third quarter, linebacker Erik Walden bites on the inside play to Gore, which left the edge of the field wide open and led to Kaepernick racing 56 yards for a backbreaking touchdown.
The Atlanta Falcons did a much better job of containing Kaepernick on the ground, but that doesn't mean that they didn't have their own share of issues defending the read-option.
In fact, it was in "properly" defending Kaepernick that the Falcons left themselves open for the fourth-quarter touchdown run by Gore that gave the 49ers the lead.
As you can see, on the play the Atlanta linebackers are focused on Kaepernick, and the edge is set to prevent Kaepernick from taking off outside, but all Kaepernick then has to do is hand it off to Gore, who scampered through a huge hole for the score.
Simply put, there's no "easy" way to stop the option. It calls for the interior defenders to be stout at the point of attack and for the outside defenders to recognize in an instant what Kaepernick's intentions are with the ball.
So basically what we're looking at is two solid NFL defenses facing uphill battles against a pair of red-hot quarterbacks.
First one to the top of the hill gets a shiny trophy and a trip to Disneyland.