KANSAS CITY, Mo. -- Defensive coordinator Steve Spagnuolo immediately laid out the priority for the Kansas City Chiefs in the first team meeting of the offseason. The players could have guessed it.

The Chiefs had the worst defense in the NFL last year when opponents moved inside the 20, allowing a touchdown 77% of the time. Their red zone defense was costly for the Chiefs in Super Bowl LV, when they allowed the Tampa Bay Buccaneers to score three TDs from inside the 20. And it was costly during their two regular-season losses, when the Chiefs gave up seven touchdowns in eight red zone tries.

"If we had just played 50% better in the red zone last year, it would have made a huge difference," Spagnuolo said last week. "Certainly, when people got in the red zone it was a challenge for us."

The Chiefs were tied for ninth in red zone defense in 2019 when they won the Super Bowl, allowing a touchdown 51% of the time.

That's why Spagnuolo in that meeting with defensive players laid out his three biggest reasons why the Chiefs were lousy inside the 20 in 2020. He felt they too often were beaten physically, that they made too many mental mistakes -- such as blitzing from the wrong spot or not carrying out the pass coverages properly -- and Spagnuolo said he frequently put the defense in a bad spot with his scheme calls.

The Chiefs spent portions of the first two practice sessions working on it.

"Did we have perfect red zone days these last two days?" linebacker Anthony Hitchens said. "No, not really but there are things we see from the offense that we see around this league. We're getting work at it in May and not waiting until Week 1 or Week 3 or 4.

"We've all got it in the forefront of our mind. We know in order to get better at it we have to work at it."

Spagnuolo said good red zone defense starts with stopping the run. The Chiefs did a decent job of this last season, allowing 2.94 yards per rush. That was slightly more than the league average of 2.90.

"We don't want to allow teams to run the ball," Spagnuolo said. "We really do want to force them to throw it and then have that tight coverage. Down there, the throwing lanes get tight [and] you try to force them into throwing into those tight windows."

This is where the Chiefs let down last season. Opposing quarterbacks had a QBR of 89.7 in the red zone, which was 29th. The league average was 70.3.

The Chiefs were also one of four teams without an interception from inside the 20.

In 2019, opposing quarterbacks had a QBR of 41.5 against the Chiefs in the red zone. The Chiefs also had a league-high four interceptions, including one in the end zone by safety Daniel Sorensen in the final seconds that helped the Chiefs preserve a seven-point win over the Chargers.

"Teams are going to be able to put drives together on us," defensive back Tyrann Mathieu said. "It's up to us, it's up to the players to really go out there and try our best to keep guys out of the end zone. That's going to give our team a greater chance to win, if we're able to make teams throw the ball in the end zone instead of running the football in.

"We've been harping on it. Coach Spags has really been harping on the details of it. That's something I would love to see us get better at."