This is going to sting for a while.

The Denver Broncos as we knew them are gone. We knew them as the defending Super Bowl 50 champions, a team famous for its historic defense.

The Denver defense of 2016 are nowhere close to the caliber of last year’s unit.

A clutch, second-half performance by Broncos quarterback Trevor Siemian went for naught Sunday night when the Kansas City Chiefs and Alex Smith drove not once, not twice, but three times to score on their final three drives to rally for a stunning, 30-27 victory in overtime.

"It's tough,'' said Broncos' safety Darian Stewart, who got a fresh $7 million signing bonus with his new contract Saturday but not a win Sunday. "This is going to hurt all the way until December the 25th.''

The Broncos and Chiefs play again Christmas night at Kansas City's Arrowhead Stadium. By then, the Broncos will likely be playing for their playoff lives. This loss drops the Broncos to 7-4, which as is stands now would leave them out of the playoffs. Adam Gase's Miami Dolphins are also 7-4 but have claim to the No. 6 and final playoff seed by virtue of a tiebreaker.

The Chiefs improved to 8-3 to stay within a game of first-place Oakland in the AFC West.

It may be way too early to recite the playoff scenarios, but perhaps the Broncos could use a sense of urgency in realizing they might be in trouble with five games remaining in the regular season. After Broncos head coach Gary Kubiak let Brandon McManus attempt a 62-yard field goal with 1:08 left in overtime, the Chiefs had great field position when the kick came up well short.

"My thing is we're going to try to win around here,'' Kubiak said. "I made that decision. It just didn't work out.''

Starting with the ball at the Denver 48, Smith drove the Chiefs down to the 16-yard line and Cairo Santos won it with a 34-yard field goal as time expired. Santos kick hit the left upright and careened in.

"That's about as tough as a loss as you can have,'' said Broncos defensive end Derek Wolfe. "Especially when we have them fourth and 10, we stop them, we win the game. We let them have it. We just made too many mistakes. It wasn't just that. I could point out like five different penalties where it was, 'Here, have the game.''

The Broncos committed a whopping 15 penalties. One cost them four points. Late in the third quarter, the Chiefs kicked a short field goal for a 12-10 lead. But the Broncos overstacked seven players on one side of the longsnapper -- a no-no that gave the Chiefs 5 yards and a first down. The Chiefs took the ball at the 12 and scored three plays later on 3-yard touchdown run by Chiefs' speed weapon Tyreek Hill, who has suddenly become the NFL's version of Christian McCaffrey. Hill scored touchdowns on an 86-yard kickoff return, the 3-yard run, and 3-yard reception -- the first player since Gale Sayers in 1965 to pull off the touchdown hat trick.

"They told me that after the game and I was like, 'Man, that's great,'' Hill said. "Everybody is going to congratulate me but it's more than me out there on the field. I've got teammates, those guys did a great job helping me weave my way through traffic and creating lanes for me to use my speed.''

Instead of leading 12-10 with the field goal, the Chiefs were up 16-10 with the touchdown.

"Me and Sly (Williams) screwed up on the field goal, we lined up on the same side,'' Wolfe said.

Oh, how those 4 points came back to haunt the Broncos. On a night when Broncos quarterback Trevor Siemian might have been the best player (apologies to Kansas City's Hill), the Denver defense could not stop the Chiefs when victory seemed certain.

The Broncos were up 24-16 with 3 minutes remaining in regulation, but the Chiefs and quarterback Alex Smith drove 75 yards to tie it on a 3-yard touchdown pass to Tyreek Hill with 12 seconds remaining and 2-point conversion pass from Smith to tight end Demetrius Harris.

The touchdown to Hill was initially ruled down at the 1-yard line but as time was ticking down to 1 second, referee Pete Morelli called for a review. The ruling on the field was overturned and the Chiefs had the tying touchdown and a chance to pull it out in overtime.

Siemian completed 20 of 34 passes for 368 yards, three touchdowns and no interceptions – the second time this year he’s had a 300-yard-plus game with at least three TD throws and no picks. Not bad for a guy who has to be mindful of a swinging gate at right tackle and block out weekly public chatter that he needs to be replaced.

"We don't need to replace him," Wolfe said. "We need to protect him.''

Each of Siemian’s touchdown passes were worthy of the 10 o’clock highlights. The first followed a cartoonish, sideline left-to-sideline right scramble before he zipped a perfect 6-yard touchdown pass to No. 4 receiver Jordan Taylor on the far right side of the end zone.

"It was all Trevor,'' Taylor said. "He did a great job staying alive. I think I might have changed directions seven or eight times trying to give him a window. He wound up doing an excellent job finding me in the corner and throwing a strike.''

The second was a pinpoint, arching pass to the left corner of the end zone that dropped wondrously into the arms of No. 2 receiver Emmanuel Sanders for a 35-yard touchdown – which was a couple plays after Siemian and Sanders hooked up for a 64-yard completion.

The third was a 76-yard loft down the left sideline to No. 5 receiver Bennie Fowler III.

"He's a helluva player, I'm proud of him,'' Wolfe said of Siemian. "He's got (guts) of steel. Everybody's talking about how (bad) you are. And he stands in there and makes plays. He's going outside the pocket. He's doing everything he can.''

In the beginning of this late-November game, the prime-time NBC audience was treated to all the imagination of vanilla ice cream and black high tops.

Many a Sunday nap has been taken along the Front Range the past two years by Denver Broncos watching fans their offense perform in no particular manner.

But the Broncos at least attempt to go north and south with the football, or the direction of the goal posts. If the Chiefs were a basketball team and Smith were their point guard, they’d be famous for their four-corner offense.

Whether it’s third-and-6, or third-and-20, Smith seemingly throws every pass toward the sideline, along the line of scrimmage.

It was fitting, then, that after a scoreless and offensive-less first quarter, the Chiefs scored the first 9 points on back-to-back plays in which their offense watched from the sidelines.

Chiefs’ pass rusher Justin Houston stripped sacked Siemian in the end zone with 6:20 remaining in the half, the fumble recovered by Denver left tackle Russell Okung for a safety.

Earlier in the game, Houston so repeatedly beat Broncos right tackle Ty Sambrailo, Denver head coach Gary Kubiak had no choice but to yank the second-round pick from Colorado State and re-insert Donald Stephenson.

In the Broncos’ previous game at New Orleans, Stephenson was pulled and replaced by Sambrailo.

After the safety, the Broncos used punter Riley Dixon to boot from the 20 on a free kick. The Chiefs’ sensational punt returner, Hill returned it 86 yards for a touchdown, slapping a high 5 to a teammate on the 5-yard line on his way in.

Defense and special teams made it 9-0 Chiefs. Soon after the Broncos got the ball back, Houston and his three sacks had to leave the field because of a shoulder injury.

With Houston out, Siemian was able to complete passes of 14 yards to Emmanuel Sanders, who also drew a 15-yard unnecessary roughness penalty from Chiefs safety Eric Barry and the Broncos were able to move the ball into field goal range. Brandon McManus converted from 33 yards to bring the Broncos within, 9-3 to end the first half scoring.

The Broncos mustered just 124 yards offense in the first half. Siemian was 9 of 15 but for only 89 yards. He was sacked four times, three times by Houston.

The Chiefs had just 49 yards of offense with Smith completing just 5 of 12 passes for 26 yards. He was sacked twice on the Chiefs’ final possession with Von Miller in on both.

And yet Smith was up 9-3 at the intermission.

Miller and Houston each finished with 3.0 sacks in a mano y mano battle of the league’s elite pass rushers.

The Broncos took the lead midway through the third quarter when on third-and-goal from the six, Siemian scrambled left to avoid a Houston sack, then pivoted and went back right, leaving the pursuing Houston to go the wrong way.

Siemian traveled all the way across the field right before flipping the ball to Taylor in the end zone.

"You can't say enough about the growth that Trevor's had,'' Taylor said. "It's been fun to watch.''

In overtime, the Broncos won the coin flip and took the ball. Siemian converted two third downs with completions, then drew a pass interference penalty on a deep pass down the left sideline to Demaryius Thomas.

The Broncos were at the 20, but the drive stalled. McManus wound up nailing a 44-yard field goal for a 27-24 lead. Five years ago, the rules were such that the Broncos would have won. But because the Broncos didn't score a touchdown, the Chiefs got a chance to have the ball and they wound up tying it again with a field goal.

The Broncos' next drive ended with McManus' missed 62-yard field goal -- he said he kicked the dirt before the ball -- which in turn put the Chiefs in position to win it. They capitalized by moving the ball just enough against a Denver defense that is still very good, but no longer great.

"Usually, leave it up to us for one more dirve, that's money,'' said Broncos linebacker Brandon Marshall. "We should have won that game.''