KANSAS CITY, Mo. (AP) - The impenetrable wall that was the Kansas City defense was breached by the Denver Broncos two weeks ago, when Peyton Manning and his cohorts ran up and down the field in a 27-17 victory.
It crumbled entirely against Philip Rivers and the San Diego Chargers last weekend.
Now, what was once considered among the most fearsome groups in the NFL is a wounded one - both physically and mentally - as the Broncos prepare to return to Arrowhead Stadium on Sunday.
The Chiefs had allowed just a shade over 12 points a game during a 9-0 start, and were piling up sacks at such a rate that they were on pace to shatter the league record. But after a 41-38 loss to the Chargers that same bunch has now allowed an average of 34 points in their two defeats.
"Just like we were doing when we were winning, we need to go back and see what's up and correct it," Chiefs safety Eric Berry said, "and just keep going to work. It's not the end of the world. But we do have a sense of urgency this week to get the things corrected that we see on tape."
Things like missed tackles and blown assignments, especially in the passing game.
Manning threw for 323 yards and a touchdown without an interception at Mile High Stadium, and his offensive line never let the Chiefs lay a hand on him. Rivers gouged them even deeper, throwing for 392 yards and three touchdowns without tossing a pick.
That's more than 700 yards of passing offense in the last two games.
"We just have to hammer down," fellow Chiefs safety Kendrick Lewis said. "The little things. You can't let the little things slip. You just have to put that extra focus in."
Chiefs coach Andy Reid said after reviewing the film from San Diego on Monday that he still has plenty of confidence in the defense, even after it cracked under pressure.
Kansas City had just taken the lead on a pass from Alex Smith to Dwayne Bowe with 1:22 left when it kicked the ball back to the Chargers. Rivers led his team the other direction in less than a minute, and his 26-yard touchdown pass to Seyi Ajirotutu ultimately won the game.
Of the Chargers' seven scoring drives, all but one of them took fewer than four minutes. Three of them took fewer than two minutes. The longest took all of 4 minutes, 41 seconds.
"We have to execute better," Reid said. "The short catches, long gains, you have to negate those. Good passing teams are going to catch the football. You have to tackle them at that point."
Reid also pointed to some missed opportunities, including what would have been a certain pick by Quintin Demps at the goal line earlier in the game. Demps dropped the ball, the Chargers kicked a field goal - and three points just happened to be the game's final margin.
"We had a chance again for a couple turnovers, right down the stretch," Reid said. "The ball bounces funny, so we weren't able to pick up on that."
The secondary hasn't been helped lately by a pass rush that has virtually disappeared.
After sacking Houston's Case Keenum five times on Oct. 5, the Chiefs have managed just two sacks in their last four games. One came in a win over Cleveland and the other in the waning minutes against San Diego, and that was by Berry on safety blitz.
Tamba Hali and Justin Houston, who have 20 sacks between them, have been shut down by opposing offensive lines, and now they are both banged up.
Hali had an MRI exam on a sprained ankle Monday, and Reid wasn't sure when or to what extent he'll practice this week. Houston's partially dislocated elbow was so severe that the swelling forced the team to postpone an MRI exam. His elbow was wrapped and in a sling Monday.
It's nearly certain Houston will be out against Denver.
"Losing that caliber of players, we have to step it up, make something happen," Chiefs cornerback Brandon Flowers said. "That's what we get paid to do."