Seahawks’ Super Bowl-champion defense takes on Brock Purdy’s 49ers as Week 5’s marquee test looms

Week 5 presents one of the league’s most compelling contrasts: the Seattle Seahawks’ defense, described by CBS Sports as Super Bowl champion-level, facing Brock Purdy’s San Francisco 49ers, who enter the matchup with a 4-0 start. The appeal is straightforward. It is a meeting of San Francisco’s efficient passing attack behind Purdy and Seattle’s ability to turn games through pressure, coverage discipline, and disruption at multiple points of the defensive snap.

CBS Sports’ case for Purdy’s current form is based on his performance trajectory in this season, characterizing him as playing at the best level of any quarterback in the NFL right now. That framing matters because it defines what the 49ers are asking their offense to do, and what the Seahawks will need to prevent. If Purdy is distributing cleanly, moving through progressions, and delivering on time, Seattle’s defensive identity is tested by necessity rather than novelty.

On the other side, Seattle’s unit is being presented as a defense with a résumé attached to the moment, not just the week. The CBS Sports preview emphasizes that the Seahawks’ blueprint, backed by their recent championship, makes this a “top battle” rather than a routine schedule stop. For a defense like that, the key is turning early success into sustained pressure, forcing unfavorable throws, and limiting the run-after-catch damage that elite offenses can manufacture once the pocket breaks down.

For San Francisco, the danger in a matchup like this is that “playing well” may not be enough. The 49ers can be productive without being dominant, but against a defense billed as championship-caliber, efficiency has to be paired with rhythm. That means maintaining third-down conversion chances, protecting against sack and turnover swings, and ensuring that Purdy’s best plays are not offset by a steady diet of second-and-long situations created by negative run plays or penalties.

The matchup also carries weight in how each team is likely to view the season’s middle stretch. A 4-0 start changes the psychological and strategic calculus for a quarterback and offense, because the team can lean into its strengths while it still has room to correct mistakes. For Seattle, facing a high-functioning quarterback early in the calendar tests whether its defense can impose its will against one of the league’s more coherent passing performances.

What to watch, in practical terms, is how quickly the 49ers identify coverages and how often Purdy has time to throw, especially on early downs where his processing typically shapes the entire drive. At the same time, the Seahawks’ most reliable indicator of success will be whether they can generate pressure without sacrificing coverage, turning the pocket into a shorter runway and forcing Purdy into throws that are harder to execute cleanly.