DENVER _ For three quarters, Trevor Siemian was plodding along. He declined to take risks. He failed to deliver thrills.
Ah, but then the fourth quarter arrived.
Siemian was average for three quarters, but magnificent when it mattered most, throwing for two fourth-quarter scores.
Feeling depressed about the way the Broncos turned a virtually certain win into a painful defeat? I understand your pain. With three minutes left in regulation, the Chiefs were down by eight and needed to march 75 yards for a touchdown, and 2-point conversion, to tie the game.
The Chiefs did the required marching, turning a Colorado celebration into a jolt of agony.
A victory was virtually required for the Broncos. Falling to 7-4 leaves the NFL's defending champs in grave danger of missing the playoffs. The Broncos needed a win to keep within sight of the 9-2 Raiders, who survived a serious scare earlier Sunday from the Panthers.
The Chiefs sent the Broncos to the playoff endangered list. The Chiefs, 8-3, have not won a Super Bowl since 1969, but they have a better chance than the Broncos to win it all in 2016. If the playoffs started today, the Broncos would be watching the games.
Siemian is the main reason the Front Range can avoid mass depression after this loss.
Yes, his fourth-quarter touchdown passes to Emmanuel Sanders and Bennie Fowler were impressive, but the Siemian throw that sticks with me came on a third and 11 on the Broncos' final drive in regulation.
Denver was nursing a one-point lead when Siemian retreated into the end and rifled a pass to A.J. Derby in heavy coverage. The pass revealed Siemian's patience. He stood in the pocket, ignoring the Chiefs' pass rush.
On the pass, Siemian looked ready for any challenge this season, including any challenge offered by backup Paxton Lynch.
Three plays after the pass to Derby, Siemian lofted a pass to Fowler for a 76-yard touchdown. The Broncos led, 24-16, and victory in regulation seemed certain.
Right?
For the game's first 57 minutes, the Broncos' defense was stingy and violent and impressive. During the final three minutes of regulation, that same defense transformed to confused and porous. The defense, the soul of the team, fell apart when it mattered most.
But maybe Siemian can revive his fallen teammates. The Broncos head into the stretch run as underdogs to make the playoffs. If that sounds overly pessimistic, consider the Broncos' schedule. They must still tangle with the Chiefs, Patriots and Raiders.
This is a strange place to reside for a franchise and its fans, who have grown accustomed in recent years to dominating the AFC West.
That domination has ended.
Siemian will be asked to lead the comeback. The Broncos boast an elite defense, despite what happened in the final moments of regulation. On Sunday, Siemian showed the Broncos he's clutch and tough.
In the fourth quarter, Siemian was floating long passes to Sanders and rifling short passes to Derby. He ended any quarterback controversy. OK, he ended any quarterback controversy for at least a week.
He seized control of the game, if only for a fleeting instant.
"He played like a champ," coach Gary Kubiak said. "I think Trevor's play was tremendous. I wish he could have gotten out of here with a win. I'm proud of him."
Siemian placed his team in position for a dramatic, and vital, victory, but his defensive brethren could not stop the Chiefs.
The Broncos' season is in high peril.
Siemian can lead the rescue.
