The first time that the Seahawks and 49ers met this season, Seattle mustered all of six points in a loss. Sunday night, Pete Carroll's team hung 42 on its division rivals.
For starters, San Francisco was missing Justin Smith. The 49ers' standout defensive tackle suffered an injury during his team's Week 15 game against New England. Since then, the 49ers have allowed 70 points.
But the 49ers' issues Sunday night went beyond Smith's absence. Seattle found gaps in the San Francisco defense -- almost entirely outside the hash marks -- and went to work in those areas repeatedly.
Let's take a closer look in this week's Break It Down:
It took all of one snap for the Seahawks to expose San Francisco's issues. On their first play from scrimmage, the Seahawks lined QB Russell Wilson up in the pistol (where he was much of the night) with Marshawn Lynch to his right. Seattle had three receivers and one tight end on the field, as well.
That tight end, Zach Miller (yellow line below) flared to the right flat, while Doug Baldwin (white line) did the same flipped on the other side of the field.
San Francisco wound up covering ... really, no one.
The 49ers rushed four, kept their four defensive backs deep and sat three players in the middle of the field. Miller, and just about everyone else who ran a pattern, came wide open.
Less than a minute into the game, the Seahawks established what would be their offensive themes for the day: mixing formations, utilizing play-action and trying to beat San Francisco to the boundaries.
The strategy worked, and Seattle kept going to the well -- according to Pro Football Focus, Wilson threw a pass outside the hash marks 10 times Sunday and completed nine. And of the 150 yards Seattle gained on the ground (not counting scrambles by Wilson), 120 of them came on runs wider than the offensive guard positions.
Seattle constantly adjusted its personnel -- the Seahawks, at varying times, lined up with Wilson under center in a single-back, in the pistol with one or two backs, in an empty-backfield formation and, repeatedly, with that look from play No. 1 with two receivers on each end of the line.
They hit another big play out of that alignment in the third quarter, with Wilson finding Jermaine Kearse on a corner route as the 49ers stacked defenders in the middle of the field again:
Earlier in that drive, the Seahawks again utilized a version of that double-WR alignment to free up Marshawn Lynch for a 3rd-and-2 conversion. Miller took his spot bunched tight on the right side of the line, then Golden Tate motioned in behind left tackle Russell Okung.
Tate flared to the left as three Seahawks ran routes to the middle of the field.
Ahmad Brooks managed to generate some pressure to Wilson's right, but he found himself alone, left to deal with both the shifty QB and Lynch.
For Seattle, even with Wilson feeling pressure, this was a clear win:
Eight of San Francisco's defenders were caught inside the tackle box there, leaving the exterior positions wide open.
This is not a brand-new issue for the 49ers -- when their defense gives up yards in chunks, it often happens close to the sidelines or in the flats, as opposed to up the gut. Smith's injury exacerbated that problem, because the Seahawks were able to get outside the hash marks time and time again.
Lynch did so on the game's opening touchdown run, which headed right at Smith's fill-in, Rickey Jean-Francois. Lynch found an opening between Okung and Miller, who did a terrific job getting upfield on a block.
And you'll notice that at least one San Francisco defender had to stay put on the backside, in part to prevent a Lynch cutback -- but mainly in case Wilson kept the ball and rolled that way.
The threat of Wilson taking off on the ground gave San Francisco fits -- which was slightly unexpected, since the 49ers are able to practice against the pistol formation, zone-read look employed by Colin Kaepernick.
But Wilson's legs combined with Lynch running hard and a San Francisco defensive line that failed to win many battles left the Seahawks running wild.
Even when the 49ers put themselves in advantageous positions, they could not finish off plays. Here, San Francisco did just about all you can ask against the zone-read option. Brooks held his ground on the left edge, the 49ers plugged the middle of the field and multiple defenders were left to close off the outside.
But cornerback Tarrell Brown (red X below) hesitated ever so slightly when Wilson and Lynch came together on the handoff, which provided just enough of a gap for Lynch to turn the corner and pick up 10.
"Break It Down" has covered Cam Newton, Robert Griffin III and Kaepernick this season, so a lot of what the Seahawks did Sunday should look familiar. For a defense, however, the difficulty in defending this offense is that everyone must stay on his keys, or there is bound to be an opening.
Below, the 49ers again closed off two of three paths on the zone-read -- Wilson's run lane and Lynch's hole up the middle. But the cutback was wide open for a solid gain.
Seattle's ability to establish the pass early, then follow up with explosive run plays, left San Francisco flailing. The 49ers essentially had to choose between trying to slow the option attack and covering Wilson's passing lanes. By getting stuck between the two, though, the 49ers left everything available.
Anthony McCoy's easy 6-yard TD pass is proof of that. McCoy came in motion just before the snap and the 49ers attempted to adjust their coverage scheme accordingly ...
... but they failed. San Francisco blitzed off the edge and kept a defender stationed in the middle of the field -- meaning that six 49ers had their Wilson (or Lynch on a handoff) as their primary assignment on the play.
When Wilson rolled outside the pocket, however, he basically made somewhere between five and seven defenders totally irrelevant. McCoy slipped into open space in the flat, and a second option broke open deep in the end zone.
At the heart of the zone-read option offense is the idea that, through deception and motion, you can outnumber the defense at key points of attack. Even when Seattle was not running those zone-read fakes, those principles were at work.
On Lynch's earlier touchdown reception, for example, the Seahawks had their familiar look with one receiver and a tight end to Wilson's right, plus two receivers bunched to Wilson's left.
The pair on Wilson's blindside cleared out -- one hook pattern to the end zone and one shallow crossing pattern. Lynch, then, filled in the gap over the middle and found nary a defender in sight.
Wilson set up that TD toss to Lynch by hitting a deep ball to Doug Baldwin. The 49ers brought extra pressure on that play too, plus sat two coverage defenders down in the middle of the field.
What was left deep was one-on-one coverage with no safety help.
Wilson's numbers have risen steadily as the season has gone on, with Seattle becoming more comfortable putting the ball in his hands and the rookie QB doing a better job picking out soft spots in the defense.
NFL defenses, on the whole, have yet to adjust to the Wilson/RGIII/Newton/Kaepernick approach -- the option plays causing fits for linebackers, which in turn leaves gaping holes in the flats and, if the defense adjusts by bringing extra pressure, downfield.