BALTIMORE -- In a way, Steve Spagnuolo saw Sunday night's collapse of the Kansas City Chiefs' defense coming. Three days earlier, the Chiefs' defensive coordinator said tackling was his biggest concern headed into the Week 2 game against the Baltimore Ravens.

"If we don't make tackles against this crew, it's going to be ..." said Spagnuolo, his thought trailing off but not before indicating he feared the worst.

Those fears were realized in the Chiefs' 36-35 loss to the Ravens. The Chiefs missed numerous tackles, one of their biggest defensive problems in their first September loss since 2016.

The Chiefs weren't much better defensively the week before in their season-opening win over the Cleveland Browns, though they managed a game-winning stop on Cleveland's final drive. But then, like against the Ravens, their defensive problems were obvious enough that they're threatening to derail what could be a promising season and a potential third straight trip to the Super Bowl.

"It's only two games in and we've played two of the best teams in the conference," said safety Tyrann Mathieu, who intercepted Lamar Jackson twice Sunday -- one for a pick-six. "We have to commit to stopping the run. It has to be No. 1 with us. The [Ravens are] good. Those guys can run the ball. It was a team effort for them and it's got to be a team effort for us to stop the run. They play fast, but we just have to find a way to get back to committing ourselves to stopping the run.

"Every play isn't going to be a pass. Against these kinds of teams -- the Ravens, the Titans, the Browns -- you have to be ready to stop the run. You have to be committed. And that's not just the defensive line. That's the other guys as well. ... [Defense isn't all] sacks and interceptions."

The Chiefs had reason heading into the season to expect good things from their defense. They acquired tackle Jarran Reed, a move they thought would not only bolster their line but also free them to move Chris Jones to an edge position.

They also drafted a linebacker -- Missouri's Nick Bolton -- in the second round for the second straight year. That move, coupled with last season's selection of Willie Gay, looked like it would add more range and playmaking ability to positions that had been lacking in recent years.

Gay is on injured reserve with a toe injury and hasn't played this season.

The changes haven't worked so far. The Chiefs are last in yards (469 average) and rushing yards (202) allowed per game. They are last in win rates of pass rush (26.2%) and rush stop (42.4%). They're giving up 32.5 points per game.

"When you have the opportunity to tackle, you have to tackle," coach Andy Reid said. "When guys are in position, you have to make the tackle. We have to do a better job of getting off blocks.

"We've played the two best run teams in the league back-to-back here. But we need to do better."

It's difficult for the Chiefs to work on tackling in practice during the season. Their work this time of year is conducted mostly without contact to preserve themselves for the weekend.

But improvement is a must.

"You miss over 10 tackles in a game, that causes devastation for a defense." defensive end Frank Clark said.

The Chiefs improved defensively after a rough first half of the season in 2019. They had a game against Tennessee that year that was similar to the one Sunday night. They allowed 225 rushing yards and saw a nine-point lead in the fourth quarter disappear in a 35-32 loss.

That was the last game the Chiefs lost that season. They finished with the NFL's best scoring defense over the final six regular-season games and the Chiefs went on to win Super Bowl LIV.

It was impossible to picture how much the Chiefs would improve defensively then. It's difficult to predict a similar turnaround this year. Maybe Gay's eventual return will help.

Otherwise, it will have to happen from within.

"I just look forward to seeing us turn the page," Mathieu said. "This is an every week thing that you have to be dedicated to. I look forward to seeing us respond."