Here are 10 things that stood out about Sunday's game in Buffalo:
1. Alex Smith's toughness
If fans didn't already know how tough Chiefs quarterback Alex Smith was before this game, now they know. Smith was hit consistently throughout this game but still managed to lead the Chiefs offense to 14 unanswered points in the fourth quarter to pick up the Chiefs' sixth win of the season.
The go-ahead touchdown midway through the fourth quarter came on an Alex Smith 8-yard run, which also included contact.
2. Defensive stands and Ron Parker's play
The Chiefs defense was challenged a few times in this game, and they responded each time.
After the Bills' opening drive, they didn't score another touchdown despite having the ball inside the Chiefs 10-yard line twice.
Ron Parker was the defensive star in the final minutes of the game for the Chiefs. He made back-to-back plays in the end zone with the Bills trying to take the lead.
He was part of the defensive backfield that kept the Bills leading receiver, Sammy Watkins, to just four catches for 27 yards.
3. Dwayne Bowe stepped up
When the Chiefs offense was struggling to consistently get it going, Bowe was the guy who stepped up and made a play in the passing game.
Bowe finished the game with eight catches for 93 yards, which was a season high for him.
But no catch was bigger than his reception early in the fourth quarter when the Chiefs faced a third-and-16. His 15-yard gain set up the fourth-down run from Jamaal Charles.
4. Albert Wilson and Anthony Sherman make special teams play
The biggest play of the game was made by Albert Wilson and Anthony Sherman.
With just over nine minutes left to go in the game, the Chiefs were forced to punt the ball and rely on their defense to get it back as they trailed 13-10.
But instead, Wilson and Sherman combined to tackle and force the fumble by Bills punt returner Leodis McKelvin, and the Chiefs recovered on the Bills' 26-yard line.
5. Andy Reid's play call on fourth down
Chiefs coach Andy Reid's decision on fourth-and-1 to not only go for it, but run a counter pitch to the outside with Jamaal Charles might be the most memorable play call of the season so far for the Chiefs.
Charles took the pitch 39 yards for the touchdown and really set in motion the victory for the Chiefs.
It was a fantastic play call that was as important as it was gutsy.
6. Jamaal Charles' toughness
When you go up against a team as tough as the Bills, the only way you're going to beat them is to match their physicality. Jamaal Charles and the Chiefs did that on Sunday.
Charles left the game briefly with a stinger in his right shoulder and on the first play of his return to the field, went 17 yards up the middle.
Charles finished the game with 15 carries for 98 yards and a touchdown, chipping in three catches for 20 yards in the receiving game as well.
It's a word we've used a few different times this season to define this Chiefs team. Through all the injuries early in the season, they fought back.
Through all of the struggles on Sunday, they fought back.
The defense gave them a chance to win it in the fourth quarter by playing fantastic football earlier in the game after the Bills' first drive.
When the Chiefs fumbled deep in their own territory, the defense didn't blink and forced the Bills to settle for a field goal.
The Kansas City Chiefs visit the Buffalo Bills in week 10 of the 2014 season.
8. Travis Kelce makes the play when called
The Chiefs leading receiver coming into Sunday's game was tight end Travis Kelce, who might have only finished with two catches for 19 yards, but the 13-yard catch he made late in the fourth quarter all but sealed the win for the Chiefs.
Alex Smith bought some time in the pocket and found Kelce on a crucial third-and-8 from their own 17-yard line. That took them to the two-minute warning and didn't give the Bills a realistic chance at a game-winning drive.
9. Demetrius Harris' injury
The Kansas City Chiefs have had success this season using "13 personnel," which had Demetrius Harris, Anthony Fasano and Travis Kelce on the field together.
With Harris injuring his foot during warmups, that grouping was not an option against a fierce front seven for the Bills. Fullback Anthony Sherman seemed to take some of the snaps while lining up as a tight end.
It wasn't always perfect, but the Chiefs offense found its stride in the second half and did enough to win this game.
10. Bills defensive line
The Bills defensive line was everything they were thought to be, and they controlled the line of scrimmage for a lot of this game.
Alex Smith was sacked six times and was hit often.
The Chiefs found a way in the second half with some misdirection to get Charles a lane to the second level, and he was able to do the rest.