DENVER --After the Broncos suffered their worst home loss in four years by a 29-13 count to the Chiefs on Sunday, much of the public blame landed at the feet of quarterback Peyton Manning, who endured one of the most difficult games in a brilliant career: 5-of-20 passing for 35 yards with no touchdowns and four interceptions.

But it came when the quarterback was hurting. Badly.

Beginning Wednesday, the injury report cited a foot problem that was exacerbated by playing on artificial turf last week. Manning had also had a shoulder problem on top of that, Head Coach Gary Kubiak said. By Saturday, Manning had a rib injury that was added to the injury report.

But Manning stayed in the starting lineup. And in the wake of a loss that snapped an 11-game regular-season home winning streak, Kubiak did what a leader does: he took responsibility and admitted frustration about the fact that he "didn't make a better decision for our football team."

"Saturday, when there was more, that's when I felt like I should have said, 'Okay, no,'" Kubiak said.

"Guys want to play. That's why he's a great player. That's why he's going to be a Hall of Fame player. They want to compete. They want to do everything they can for their football team, but as a football coach, sometimes you have to say, 'No, I don't think this is the right thing to do today.'"

Manning did start, and hindered by injuries, he threw four interceptions, dropping his season-long touchdown-to-interception ratio to 9-to-17. Brock Osweiler relieved him and directed the Broncos to two fourth-quarter touchdown drives that allowed them to avert the first home shutout in franchise history.

But Kubiak made it clear: Manning is still the team's first-team quarterback, and if he can recover enough from his injuries by next week, he will start in Chicago.

"Peyton's our quarterback," Kubiak said. "If he's healthy and ready to go, Peyton's our quarterback."

But if Manning is healthy, he and the offense needs to find a way to eliminate the giveaways.

Above all, that's where Sunday's game was lost, and it's where this week's Three Keys begins:

1. Win the turnover battle.

Just four weeks ago, the Broncos were among the league leaders in giveaway-takeaway margin. The offense was tied for seventh in the league with 1.83 giveaways per game, but the defense forced 2.83 turnovers per game, a plus-1-per-game margin that was tied for second in the league.

In the three games that have followed, the Broncos have committed eight turnovers -- all via interceptions -- and haven't forced one takeaway. Twenty of the Chiefs' 29 points came off interceptions, and between giveaways, a special-teams penalty and failed attempts at on-side kickoffs, the Chiefs began half of their 14 possessions at midfield or in Broncos territory.

No matter how many takeaways you force, five turnovers is a near-certain prescription for defeat. According to pro-football-reference.com, the Broncos are the 107th team since 2008 to have at least five giveaways in a game; those teams are now 4-103.

Still, the defense put some blame on itself.

"We didn't do much to get the spark going as a team from a defensive standpoint," said OLB Von Miller, who had a third-quarter sack of Smith.

"We've been creating turnovers, [even when] giving up the short field. We just didn't do that tonight.

"All year, we just [had not] waited around and waited for somebody else to do something as a defense. We went out there and got turnovers. We just didn't do that today."

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2. Pressure Alex Smith -- but then contain him.**

The Broncos hit Smith six times, sacked him twice and kept him from doing too much damage on third downs, holding the Chiefs to just four conversions in 16 third-down attempts -- a 25-percent success rate well below the 60 percent figure amassed by the Colts last week.

Smith kept two plays alive with his feet, sprinting 12 yards on third-and-1 late in the second quarter to set up Cairo Santos' fourth field goal and 17 yards on third-and-10 to move the Chiefs into field-goal range with 8:40 left in the third quarter.

Smith didn't break the Broncos' back, but with the horrible field position that faced the defense for most of the day, he didn't need to string together much to get the Chiefs into scoring range. On five of the Chiefs' seven scoring drives, they gained one first down -- or didn't get one at all. But that was plenty to allow them to keep building their lead, kick by kick.

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3. Find offensive balance.**

As was the case last week, the flow of the game -- and a big early deficit -- forced the Broncos into pass-intensive mode. Five of the Broncos' first 13 plays were runs that picked up eight yards, but after two more passes -- one of which resulted in the Chiefs' second interception -- the Broncos were forced to go to the air, trailing 13-0. They went three-and-out with a sack and two incompletions.

The Broncos have spent more than half of their last two games -- 69 minutes, 27 seconds, to be exact -- trailing by two scores. That's not going to help any efforts to achieve anything close to balance, and that was reflected in a game that finished with 49 pass plays and 16 runs -- three of which came on Osweiler scrambles.