KANSAS CITY, Mo. — A fine mist hung in the air over the brightly illuminated stadium, a combination of fireworks residue, barbecue smoke and rain that held off for most of the cold night.

Rogue yellow streamers from the touchdown cannons zipped around over the stadium, attached to the invisible wires that helped network cameras soar over the turf.

But with 4 seconds left in the Chiefs-Chargers game Thursday night, instead of more confetti, plastic bottles and trash flew from the dumbfounded crowd.

Below, it wasn't a scene worth celebrating, at least not for the thousands that packed the stadium and began filling the parking lots surrounding Arrowhead hours before the stadium gates even opened.

Instead of the Chiefs celebrating, it was the Chargers jumping joyously as they ran off the field, jubilantly jogging around after quarterback Philip Rivers' successful two-point conversion pass to Mike Williams completed a miraculous comeback and denied the Chiefs an AFC West title with a 29-28 win.

Teams this season were 0-88 when trailing by 14 or more points in the final five minutes of regulation, according to ESPN. Rivers, once tormented by Kansas City, was 0-20 in those situations.

Until Thursday night.

Aided by rookie Dorian O'Daniel's play, Kansas City held off the Chargers at the goal line for a while. They had eight more seconds to make a stand. But Kendall Fuller's pass interference penalty gave LA a fresh set of downs.

The Chargers scored on first-and-goal from the 1 as Rivers connected with Williams with 4 seconds left for Williams' third — and most important — touchdown of the night.

It wasn't supposed to be like this. The Chiefs weren't supposed to lose to a divisional opponent in prime time, not one they'd beaten nine straight times, not on a night when safety Eric Berry returned and they could've clinched their third consecutive AFC West title.

And yet, that's what happened.

After the offense stalled deep in its own territory late in the fourth quarter, partially the result of a penalty on the kick return, the Chiefs punted with two and a half minutes left and a seven-point lead.

Rivers threw a 31-yard pass to Travis Benjamin, putting the Chargers at Kansas City's 39 with two minutes to go.

That's all the time LA, once down two scores in the fourth quarter, needed to complete the comeback.

The Chiefs jumped out to a 7-0 lead in the first after Patrick Mahomes (24 of 34, 243 yards, 2 touchdowns) turned Steven Nelson's interception of Rivers on the second play _ one aided by Berry's blitz _ into a 10-play, 49-yard drive capped off with a nonchalant touchdown pass to DeMarcus Robinson.

In a play that took 6.17 seconds to develop, Mahomes faked throwing the ball away, located his receiver in the end zone, and even as a man was hanging off Mahomes in a sack attempt, he completed the throw.

By the end of the first quarter, Kansas City built a 14-0 lead thanks to Darrel Williams' first career touchdown, scored on an 11-yard catch from Mahomes. With the absence of starting running back Spencer Ware, who was inactive with hamstring and shoulder injuries, Damien Williams was instrumental in those two scoring drives. By the end of the night, he led the Chiefs in rushing with 10 yards on 49 carries for two touchdowns. He also led the Chiefs in receiving with 6 yards on 74 catches.

Though Rivers (26 for 38, 313 yards, 2 touchdowns, 2 interceptions) eventually got the Chargers in the end zone with a fade pass to Mike Williams in the end zone, the Chiefs defense played sound football in the first half.

Led by defensive end Chris Jones, Kansas City sacked Rivers four times and picked him off twice in the opening quarters, including one in the corner of the end zone by Kendall Fuller that prevented the game from being tied at half. Jones led the team with 2 { sacks in the opening half, extending his consecutive game sack streak to 10 games, tying an NFL record.

Berry, who didn't play after halftime, led the Chiefs with six tackles at halftime. He didn't have a grand introduction to start the game, but he was celebrated loudly every time he made a play. Though he got beat a couple times, his impact was a positive influence on the Chiefs' defense, beginning with the blitz of Rivers on the Chargers' short-lived opening drive.

But for everything that went right for the Chiefs in the first half, it was still a one-score game entering the third quarter.

The Chiefs stretched it to a two-score game on the opening drive, finishing off a seven-play, 74-yard drive with a two-yard run by Damien Williams for the running back's second rushing touchdown of the season. Mahomes had to fight through plenty of contact in the first drive, getting drilled by defensive end Joey Bosa on each of the first two plays.

Though the score to open the third quarter gave the Chiefs much-needed momentum, it wasn't enough to shut the door on the Chargers.

Playing without his best receiver in Keenan Allen, who left in the first half with a hip injury, Rivers led three more touchdown drives in the second half. In the first, linebacker Anthony Hitchens got beat on receiver Mike Williams' 19-yard run. And in the second, rookie Josh Jackson, who led the Chargers with 58 yards on 16 carries, got in from three yards out with 3:49 left to play.

Jackson's touchdown made it a one-score game, and after a penalty on the kick return, the Chiefs were backed up deep in their own territory.

With a false start on Demetrius Harris, the Chiefs faced third-and-long from their own eight. Melvin Ingram and Isaac Rochell sacked Mahomes and forced the Chiefs to punt.

For the final 2 and a half minutes, Kansas City had to rely on its defense to keep the Chargers at bay. And in the end, it couldn't get the job done.