The Seahawks exposed the Patriots' biggest weakness
The loss is just the Patriots' second of the season and the first with Tom Brady at the helm since he's returned from his suspension.
While Brady and the Patriots' offense couldn't find the end zone from the goal line in four tries at the end of the game - a coincidental reversal of fortunes - it was the defense that let the Patriots down.
The Patriots surrendered 31 points to a 14th-ranked offense, on the road, coming into New England on a short week. The Seahawks scored on seven of their nine drives, gained 23 first downs, and went 6-for-12 on third-down attempts. Though the Patriots came into the game allowing the second-fewest points in the NFL, they also haven't had the toughest schedule. To date, the Patriots have only played one team ranked into the top half of the league in offense - the Steelers, and they were without Ben Roethlisberger that week.
As Ben Volin of the Boston Globe notes, one year ago, the Patriots defense finished in the top 10 in points and yards allowed. Over the course of a year, Bill Belichick has gradually deconstructed that defense, highlighted by trading top pass-rushers Chandler Jones and Jamie Collins for future draft picks. What's left, Volin writes, are "players who aren't nearly as physically talented, but are more cost-effective."
After the game, Patriots coach Bill Belichick said that the secondary, which was torched by Russell Wilson and the Seahawks' receivers, had more trouble in man coverage than zone coverage, suggesting there were individual struggles, not team struggles. Belichick said after the game, "Just didn't play it well, obviously. I think it goes without saying."
In the third quarter, the Patriots' defensive struggles were encapsulated. On first-and-10, from the Patriots' 18, Russell Wilson escaped the pocket as the Patriots' pass rush couldn't get to him against a notably futile Seahawks offensive line. Wilson, with time, threw across the field to a wide-open Doug Baldwin for the touchdown.
While Baldwin later told MMQB's Peter King that this was not "football 101," suggesting it was a risky throw, it also highlighted the Patriots' struggles. They couldn't get to Wilson and let him throw across the field to a wide-open top receiving threat.
Later, in the fourth quarter, Wilson threw what became the game-winning touchdown when the Patriots couldn't get a stop from their own 20 on third-and-eight. Wilson hit Baldwin for another touchdown, lobbing it over a beaten Patriots' secondary.
Coming into the week, the Patriots ranked 18th in defense, according to Football Outsiders. After giving up a season-high in opponent points, that number is likely to fall.
It says something about the Patriots' overall skill that, even in a poor defensive showing, they went down to the wire on a goal-line stand. Their offense is so good that they'll have a chance to win nearly every game, even against other Super Bowl contenders, like the Seahawks. But on weeks where their offense fails - as it did on the final drive against Seattle - their defense isn't proving to be good enough to carry them.
The Patriots don't face another dynamic offense for the rest of the season. Of their remaining seven games, the only team they face in the top 20 in Football Outsiders' offense is the Miami Dolphins. The Patriots may be able to hide their defense or improve it against a batch of weak opponents over the next seven weeks.
However, the common refrain in sports is that defense wins championships. In the postseason, the Patriots won't be able to solely rely on their offense.