Seahawks running back Bryce Brown breaks through for a touchdown run early in Sunday's 36-6 Cardinals' loss.
The Cardinals' defense rode a wave of post-Tyrann Mathieu emotion to its best defensive performance of the season last week against Green Bay, allowing only eight points.
On Sunday, the tide moved away and the defense was beached helplessly on the shore.
While it's debatable whether Mathieu's presence could have helped or not, the Cardinals had trouble keeping the Seattle offense in check in Sunday's 36-6 loss. Quarterback Russell Wilson was 19-of-28 for 197 yards and three touchdowns, throwing darts to a variety of targets.
He moved around the pocket comfortably, as a defense that racked up nine sacks against the Packers rarely gave Wilson trouble.
"Russell's a heck of a quarterback," coach Bruce Arians said. "He was on fire today. I just don't think we played up to our standard defensively. He didn't hit the ground until late in the (third) quarter."
The pass rush was subpar and the coverage concerns that popped up following Mathieu's season-ending injury were given legitimacy. Wilson and Tarvaris Jackson combined to complete 69 percent of their passes, and most disconcerting, several passes went to wide open receivers.
"I feel like a lot of it was training camp-type stuff," linebacker Kevin Minter said. "Myself especially. My eyes … it was like Linebacker 101. My eyes were everywhere. You see some of the gashes. We have to get back to the fundamentals. They didn't do anything special, that we didn't know they were going to do."
The Cardinals have shown they can be a dominant defensive unit in stretches but will now enter the postseason with this effort lingering in their minds. Cornerback Patrick Peterson said the issues were small and that the group will bounce back.
"Every time we step on the field we want to dominate," Peterson said. "Today we just couldn't find our mojo."
One phase that has always been strong this season has been the run defense, but Seattle's third-string running back, Christine Michael, finished with 17 carries for 102 yards, including a 45-yard scamper in the first quarter.
The Cardinals gave up a season-high in points one week after creeping into the top-five in the NFL in points allowed. Thirty of them were scored by halftime in a game that was over in the type of quick fashion the Cardinals were used to inflicting on opponents.
A lack of intensity was pointed to as a root issue, and the Cardinals hope they can rebound next time out in the NFC divisional round, when the win-or-go-home playoffs begin for them.
"It's definitely upsetting, especially the last two games we had where we played really good ball," cornerback Justin Bethel said. "And then a divisional rival like that, and to end it off the way we did, I'm disappointed in me for the fans. I know they're disappointed in us. All I can say is, we're going to go out there and work and get ready for the next game."