[2][3][4] Nonetheless, the Bills and Chiefs have had many notable moments in NFL postseason history, including the 1966 AFL Championship preceding the first-ever Super Bowl, and the 2021 AFC Divisional playoff game, which is often nicknamed 13 Seconds.

[5][6] Buffalo is one of 4 teams in the AFC with a winning overall record against Kansas City (the others being the Cincinnati Bengals, Indianapolis Colts and Pittsburgh Steelers).

In 1991, both teams met in the regular season at Arrowhead Stadium where the Chiefs would defeat the then-defending AFC champion Bills by a score of 33–6.

[14] Prior to the 1993 season, the Chiefs acquired quarterback Joe Montana from the San Francisco 49ers and also signed running back Marcus Allen, both former Super Bowl MVPs.

Joe Montana, returning to the Chiefs' lineup after a missing a month due to an injury, would throw for two passing touchdowns in the victory.

Montana would suffer a concussion on a three-way sack from Bruce Smith, Phil Hansen, and Jeff Wright, early in the third quarter, which forced Chiefs backup quarterback Dave Krieg into the game.

To this date, every game in the current decade between the two teams has featured quarterbacks Josh Allen of the Bills and Patrick Mahomes of the Chiefs, who have become key figures in the rivalry.

[21] Both quarterbacks have been noted for their physicality, strong arm strength, and mobile styles of play, where they have demonstrated to escape running with the football while under pressure as well as effectively scramble when called upon.

[25] Bills head coach Sean McDermott later mentioned he was more comfortable drafting a quarterback early in 2018 as opposed to 2017, choosing Allen 7th overall in 2018 after taking Nathan Peterman in the 5th round the year prior.

Buffalo would take an early 9–0 lead, but the lead would not last, as Kansas City took control of the game in the second quarter, and cruised to a 38–24 victory to repeat as conference champions, allowing them to advance to Super Bowl LV (only to lose to NFC Champions Tampa Bay, led by Buffalo's long-time intradivision nemesis Tom Brady).

With 13 seconds remaining, Allen threw a touchdown pass to wide receiver Gabe Davis to give the Bills a 36–33 lead.

However, Mahomes would lead a 44-yard drive with the little time remaining, resulting in a 49-yard field goal by Chiefs kicker Harrison Butker to tie the game and send it to overtime.

Kansas City took a 20–17 lead on a field goal with under 10 minutes to play, then the Bills defense forced a three-and-out on the Chiefs next possession.

On the Chiefs' final possession of the game, Patrick Mahomes was intercepted by Bills cornerback Taron Johnson, preserving a 24–20 victory for Buffalo.

A play later, Kansas City advanced the ball down to Buffalo's 3-yard line with a great opportunity to extend their lead to two scores.

However, Kansas City wide receiver Mecole Hardman fumbled the ball out the side of the end zone for a touchback, thus allowing Buffalo to regain possession and remain in the game.

After the teams traded punts, the Bills advanced the ball into Kansas City territory, but their drive stalled in field goal range.

This allowed the Chiefs to select wideout Xavier Worthy,[40] who had just run the fastest 40-yard dash time in NFL Combine history,[41] while the Bills traded down again with the Carolina Panthers and out of the first round, ultimately drafting receiver Keon Coleman with the 33rd overall pick.

[42] The Bills' decision to trade down with the Chiefs again was criticized by the media and fans in the immediate aftermath, especially in the wake of Kansas City winning their third Super Bowl with Mahomes while Buffalo had yet to make it with Allen.