Their Week 6 meeting in 2020 ultimately decided who would be home when the Buffalo Bills and Kansas City Chiefs met again in the playoffs last January.
The home team won, of course, and the Bills went home one game short of the Super Bowl.
Their Week 5 meeting this season could wind up deciding the same thing following the Bills' victory over the Houston Texans and the Chiefs' win in Philadelphia on Sunday.
Regardless of what we may hear coming out of both camps in the coming week, next Sunday night's showdown in Kansas City between the Chiefs and Bills will mean everything and likely will be the most important regular-season game the Bills have played since Sean McDermott became coach in 2017.
Here is the reason: Homefield advantage.
The Bills are 2-0 at home and 0-3 on the road in the playoffs under McDermott.
Yeah, we know that might be different if not for perhaps the most egregious NFL officiating error of all time, which is saying something, considering its dubious history.
The Bills Mafia doesn't need to be reminded of the play, but we're going to do it anyway. Cody Ford's textbook clean block that ironically now is used by the league as an example of a proper technique in blindside situations was ruled to be illegal, costing the Bills a chance to try a game-winning field goal against the Texans two postseasons ago. The Texans went on to win in overtime.
Anyway, an argument can be made that home field matters to Kansas City too, because coach Andy Reid is 0-2 in road playoff games with the Chiefs.
So how do the Bills conquer their top nemesis?
Glad you asked. Here are three keys.
Get after the quarterback
You don't need to split the atom to be able to understand that even the finest quarterbacks in league history, from Johnny Unitas to Tom Brady and everyone in between are most fallible when under duress.
The Bills coaches and general manager Brandon Beane knew their team didn't put enough pressure on Patrick Mahomes, the league's most dynamic quarterback. Then they sat at home and watched how the Tampa Bay Bucs did and won the Super Bowl largely as a result.
Improving their pass rush thus became the Bills' offseason mantra, and they followed through by adding to their stable of defensive ends with veteran Efe Obada and rookies Greg Rousseau and Boogie Basham.
The Bills know they may not be able to beat the Chiefs even with a great defensive effort that makes Mahomes uncomfortable throughout. But they also know there's no chance whatsoever to pull out a win if they don't hit him and chase him around.
Be aggressive on fourth down
After the playoff loss, McDermott admitted he might have done things differently instead of having Tyler Bass come out to kick field goals on fourth-and-3 from the 33, fourth-and-goal from the 2 and fourth-and-3 from the 8.
Beating the Chiefs requires taking a certain amount of chances, and keeping your offense on the field on fourth-and-short inside their territory should be automatic as long as the game is still within reach of both teams.
Almost all conservative instincts need to be overriden.
Commit to the running game
This is important for two reasons: Keeping Kansas City's offense off the field and exploiting a defense that this year seems vulnerable in that area.
Going into Sunday's game against the Eagles, the Chiefs had given up 481 rushing yards and seven TDs on 89 attempts. That's an average of 5.4 yards per carry.
Obviously a win in early October doesn't guarantee anything. But it can make a difference in the end, as we saw last season.