Teams without top cornerbacks have not had many examples of consecutive playoffs, because in this day and age, good cornerbacks who can keep an eye on receivers are often very valuable.
However, 49ers and defenders coordinator Demico Lanes have made up for the flaws, finishing the Cowboys and Packers, and the playoff defensive total EPA has increased by six points compared to the regular season.
The 49ers' two playoff defenses have been at a high level, with an EPA of -0.18 against the Cowboys and -0.13 against the Packers, the third lowest EPA offensive EPA of the Season and the second lowest in the Packers' game of the season. In addition, the backwater game against the Rams in Week 18 also controlled the opponent's offensive EPA at -0.14, an overtime reversal that had trailed by 17 points.
No good cornerbacks, no problems
The 49ers are the only teams in the division to play at least 800 slots without any cornerbacks this season, and most teams have two such cornersbacks. The 49ers' most commonly used cornerback is Josh Norman, but he has fallen out of favor and is no longer even a starter. As Emmanuel Mosley and Amburi Thomas began to be the first starters, the 49ers stopped staring at people. The regular season 49ers were 18.7 percent more used, the league's 22nd, compared to just 14.7 percent in the playoffs.
Throughout the season, the use of people in Lanes has shown a downward trend:
Even under the leadership of former DC Robert Saleh, the 49ers rarely used a lot of man-to-man defense, and even fewer in the second half of the season. They couldn't accept a one-on-one defeat, so the use of area defense began to skyrocket, while running from the inside out to match the receiver's route, which forced the quarterback to hold the ball for a long time until the rushing pass group engulfed the protective pocket.
The man in the middle
Fred Warner, a centerback, is at the heart of the 49ers defense and is an all-around line matcher. The former BRIG Young linebacker seems to have a 360-degree view. He has a complete skill pack to suit the 49ers' different types of defensive modes.
In week 18 of the game against the Rams, when he smelled the route fit, he immediately closed the window of the receiver running behind him.
In the following attack, he extended all the way to Cooper Karp's deep curl route, blocking the pass window.
Although it was a complete process, Warner was feeling the deeper route behind Karp while observing Karp's route. If the slot corner guard has not slipped, he should be able to intercept it in front of the first line of attack.
The overtime cut that locked up a playoff spot, Warner's fluidity of backing (red socks in the middle) worked perfectly with cornerback Daquez Denal as both felt the route in front of them twist inward, and then both squeezed back to block the pass window.
The 49ers' most commonly used cover3 system to counter the trips formation requires the only deep guard to go to the side of the three receivers to defend long passes, and a defender on the weak side to help the security guard on the side of the three receivers.
Here's a vertical route that Warner uses this technology to combat the quick slot takeover:
A cohesive team
Outside of Warner, the 49ers followed the principle of matching catcher routes, establishing connections between area defenders.
The following also comes from the Cover3 versus trips formation, which eventually led to the 49ers' tackle:
In this defensive show, linebacker Dre Greenlow must match the innermost of the three receivers, which leaves the shallow zone empty, which the league offensive team usually uses to attack. In the 49ers' defensive reaction, the shallow linebackers were taken away, and a defender on the strong side would rotate to fill the gap. It may seem like a simple job, but when the first priority is to prevent the opponent from attacking vertically, it's easy for area defenders to forget to go to shallow areas.
These defenses may not be seen by everyone because of the angle of the broadcast, but these are important, especially for the 49ers defense. They must maintain the integrity of the area defense without forgetting to match the route, because they do not keep an eye on people.
Against the Packers and their world number one receiver, Davante Adams, the 49ers' defense sometimes double-bagged Adams to block the pass window when two defenders were removed from their area of responsibility.
The 49ers have two defenders staring at Adams (left side of the screen). It's one of the few times they can let cornerbacks interfere with Adams at the starting line, as players behind them will assist in defending. Rogers looked at Adams at first, and when he saw the bag clip, his gaze moved elsewhere. Warner was chasing the vertical route along the center of the court, while slot corner guard Kevin Williams felt the inside turning route cross in front of him, eventually blocking the pass window.
In the last four games, the 49ers defense has played an important role in beating the quarterback.
When the defensive group can remain efficient against the top attacking group, then they can combine the rushing pass, not only Nick Bossa, all the rushing passers can threaten the attack.
Straight pound the yellow dragon
The debate about who is more important, punching and countering, has always been strange to me, because they are not opponents, but a linear process of symbiotic relationships. The 49ers are a good example of this, with their best defender playing a position that seems less valuable — an interior guard who, combined with excellent coaching and system management, creates enough time for the team's rushing passers to chase quarterbacks.
The 49ers sometimes had to rely on rushing to pass, and in the regular season and playoffs, the 49ers made heavy use of area defense while rushing to pass the fifth in the league with a 58.5% win rate.
Bosa Jr. is clearly their best crosser (PFF cross score 90.3), but after getting Charles Omenihu (PFF rush score 77.5) in mid-season trades and ArdenSkie (PFF rush score 77.0) signed on a one-year contract last spring, they took the 49ers' rush to a new level.
Their trick to prevent transmission is to rush the pass, and the trick to rush the pass is to prevent the pass. You can't separate them, and Demico-Lanes has done a fantastic job of bringing the two units together.
In recent weeks, Gallopolo and the 49ers have been lucky enough to pass consecutively, but to win the National League championship, the defensive group limiting the Rams offense is the first step.