"In the Chiefs game, what we didn't do, we didn't get off the field on third down because we didn't make plays," defensive coordinator DeMeco Ryans said after Thursday's practice. "We busted coverages. We weren't where we were supposed to be. We didn't do our job, and when you don't do your job consistently, you'll get embarrassed, as we did in that Chiefs game.
"And it's nothing that they did that surprised us. It's guys just being on it each and every snap."
Yes, the 49ers defense was embarrassed, but since then, it has surrendered an average of 10 points per game, including this past Sunday's shutout of the New Orleans Saints. The unit ranks No. 1 in the league in total yards allowed and points allowed.
Sunday will be another tough test, though. The 49ers defense will have to stop the Miami Dolphins, who own the No. 3 offense in the NFL. They have won five straight and scored 30 or more points in their last four games.
The 49ers defense is ready and eager to prove that the Week 7 embarrassment against the Chiefs was an anomaly.
"Each week is different," Ryans said. "We had a bad week. It happens in the NFL. It happens. You have bad weeks, and that's [how] I look at the Chiefs game. It was a bad week, and we did not play up to our standard. So it's about our guys holding up our standard each and every week, and if we do that, we make it tough on offenses to go against us because we're just doing what we're supposed to do."
The two teams are very familiar with each other. Mike McDaniel, the 49ers' former offensive coordinator, is the Dolphins' head coach. His run game is powered by two former 49ers players—Raheem Mostert and Jeff Wilson Jr. Of course, the 49ers defense is very familiar with the Dolphins offense too.
"It does look very familiar," defensive end Nick Bosa said on Wednesday. "The run-game stuff, definitely used to it a little bit with going against [49ers head coach and offensive play-caller] Kyle [Shanahan] in camp and obviously going against Mike throughout the years."
Bosa and the defense know McDaniel will probably throw a few wrinkles at them on Sunday. The 49ers will have their hands full on Sunday.
"The Dolphins, their offense is very efficient because of the quarterback," Ryans said. "Tua [Tagovailoa] is very efficient at not only getting the ball out quick, but the accuracy, and the way he delivers the ball. That allows the offense to be as efficient as they are. And you add the playmakers in that he has with [Tyreek Hill], [Jaylen Waddle], and [Raheem Mostert], those guys all have elite speed and big-time play-making ability where they can take an intermediate throw, and they can make a guy miss and go to the house."
"... I think that's where this offense really lights it up because each throw, it doesn't have to be a 50-yard bomb down the field. It can be a screen behind the line of scrimmage, and these guys have the speed and the play-making ability to make guys miss and go to the house."