ORCHARD PARK, N.Y. -- The Kansas City Chiefs ran out of the late-game heroics that made them appear unbeatable.
Josh Allen and the Bills ended the two-time Super Bowl champions' bid for an undefeated season with a 30-21 win Sunday. Kansas City (9-1) now turns its focus to maintaining its position atop the AFC -- it leads Buffalo (9-2) by a half-game -- and shoring up the flaws that finally contributed to a loss.
"The undefeated thing was cool," Chiefs quarterback Patrick Mahomes said. "But that's not our ultimate goal."
Mahomes, of course, was referring to Kansas City's quest to become the first team to win three consecutive Super Bowls.
To achieve that, the Chiefs have some things to work on after they lost for the first time in 16 games (including playoffs) dating to last season.
Mahomes was unable to lead what would would have been his fifth fourth-quarter comeback of the season. The Chiefs provided no late-game dramatics, such as the blocked field goal as time expired to secure a 16-14 win over Denver a week earlier.
And Kansas City's defense was unable to contain Allen when it mattered. The Bills quarterback sealed the victory with a 26-yard touchdown run on fourth down with 2:17 remaining.
Perhaps the Chiefs can win in the long run after losing.
"I'm hoping that it is a benefit," Mahomes said. "I feel like we were just coming away with these wins at the end of games. And I think it's going to spark us to have more urgency, especially in the start of football games, especially with the offense."
Mahomes got off to a slow start by throwing an interception on the second play from scrimmage and did not complete a pass until Kansas City's third possession. He finished 23-of-33 passing for 196 yards with three touchdowns and two interceptions and oversaw an offense that crossed midfield just three times, went three-and-out three times, punted four times and finished with a season-low 259 yards.
In a showdown between two of the NFL's top quarterbacks, Mahomes was outplayed by Allen, who finished 27 of 40 for 262 yards with a touchdown passing, the rushing TD and one interception.
"That was a guy making a play in the big moment," Mahomes said, referring to Allen's TD run. "Whenever the play is not there, he does a great job of making plays happen. And that's what he did on that last play."
It was the type of game-winning play the Chiefs are used to making.
But the Bills neutralized the Chiefs' playmakers.
Tight end Travis Kelce had two receptions on four targets for eight yards after gaining 254 yards on 32 catches over in his past three games. Kansas City's offense couldn't find a spark from trade deadline addition DeAndre Hopkins, or the return of receiver JuJu Smith-Schuster.
Backup tight end Noah Gray caught two touchdown passes, with Xavier Worthy scoring on a 10-yard catch.
Coach Andy Reid lamented the Chiefs allowing the Bills to convert 9-of-15 third downs, along with Allen's decisive scoring run on fourth down. The Bills held the ball for 34:03 against a Chiefs team that came in leading the NFL in average time of possession.
"I think if we get off the field on third down, it's a totally different landscape of the game," Reid said.
Reid cited the Chiefs' loss to the Raiders last December that sparked their run to a third Super Bowl title in four seasons.
"That's absolutely what we need this to be," Reid said. "It needs to be something that we build off of. That's something that we need. A reality check for us."
It's possible the Chiefs and Bills will meet again in January. Though Mahomes dropped to 1-4 in regular-season starts against the Allen-led Bills, he's 3-0 against them in the playoffs.
"It's going to take your best football to beat great football teams. And we didn't play our best football today," Mahomes said. "All the respect to them. That's going to be a good football team that we'll probably see again."