How the Legion of Boom shut down Kaepernick, 49ers

After blowing fourth-quarter leads in consecutive games, the Seattle Seahawks defense responded to the challenge against the San Francisco 49ers, allowing 142 total yards in a 20-3 victory Thursday night. Of the 49ers' 11 drives, nine ended with a punt, one with a made field goal and one with the end of the first half.

Legion of Boom brings the pressure

The Legion of Boom was able to generate a pass rush all night, logging a season-high six sacks. The Seahawks defense has 13 sacks over the past three games after recording six over the first season's four games.

Even the mobile Colin Kaepernick could not avoid the Seahawks' rush, going 1-of-5 for eight yards when under duress. More shocking than the six sacks he took, however, was the fact that he did not scramble once. This was the first start of Kaepernick's career in which he did not have a rushing attempt. Kaepernick’s Total QBR was 9.0 on Thursday, his third-worst in a regular-season start.

The Seahawks forced the 49ers to punt on 82 percent of their drives, giving Seattle the three highest percentages of defensive drives ending in a punt in a game this season (Week 3 vs. Bears, Week 4 vs. Lions).

Seahawks continue dominating 49ers

Struggles of this kind have become a habit for the 49ers, who have been held to seven points or fewer in three consecutive games against Seattle and four of their past five regular-season meetings.

San Francisco posted 142 total yards, its fewest in a game since 133 in Week 9 of 2006 against the Vikings. The 49ers' eight first downs are tied for the second-fewest in any NFL game this season (the Bears had seven in Week 3, also against the Seahawks). There have been four instances of a team recording 10 or fewer first downs in a game this season, and the 49ers own three of them.

The Seahawks have beaten the 49ers four straight times (including playoffs), the second-longest win streak against San Francisco in team history.

Chancellor a major factor

Kam Chancellor’s return to the Seahawks in Week 3 has been key, as the Seattle defense didn't allow an offensive touchdown for the third time in the five games he has played.

Chancellor has played 11 games since Week 12 of last season, and the Seahawks have held their opponents without an offensive touchdown in seven of those games. No other team has more than three such games in that span. In the two games he missed this season, the Seahawks allowed five offensive touchdowns combined.