KANSAS CITY, Mo. — Tom Brady, Peyton Manning, Philip Rivers, Ben Roethlisberger, Drew Brees, Aaron Rodgers.

These NFL quarterbacks used to be at the top of the pecking order for best quarterbacks in the league over the past two decades. With all but two of these quarterbacks out of the league, a new QB1 class is emerging and coming into its own.

Lamar Jackson, Kyler Murray, Joe Burrow, Justin Herbert, Dak Prescott are rising to the top. And a new rivalry is emerging among the best of the new wave of top NFL quarterbacks.

Patrick Mahomes vs. Josh Allen.

Sunday’s AFC Divisional Round game between the Kansas City Chiefs and the Buffalo Bills will be the fourth time that these teams will have played each other in the past two seasons. For two straight years, it’s been matchup in October, and then a do-or-die game in the playoffs.

In the first game in 2020, the Chiefs won handily 26-17. Chiefs running back Clyde Edwards-Helaire ran for over 150 yards, Mahomes threw for 225 yards, two touchdowns and only five incompletions. Allen was held to 122 passing yards and 42 rushing yards.

When the two met again later in the season for the AFC Championship, it was a similar result. After Buffalo jumped to an early 9-0 lead, KC went on a 38-6 run before the Bills scored another touchdown late in the fourth quarter. The Chiefs won 38-24.

Mahomes threw for 325 yards and three touchdowns, tight end Travis Kelce caught two touchdowns, receiver Tyreek Hill gets almost 200 yards and the Chiefs go to the Super Bowl. Josh Allen threw for 287 yards and ran for 88 while throwing two touchdowns; one touchdown and lots of yards coming when the Bills were already down big.

But in 2021, the roles switched.

Allen threw three touchdowns and 315 yards while also rushing for 59 yards and a score. Mahomes threw two touchdowns but also two costly interceptions. The Bills dominated at Arrowhead Stadium.

And that brings us to where we are now: two evenly matched teams facing off once again in the playoffs and two young quarterbacks with impressive playoff resumes.

The Chiefs and Bills may be the most evenly matched teams in the playoffs: athletic/strong-arm running quarterbacks, explosive (sometimes inconsistent) offenses and aggressive defenses that thrive off of turnovers.

Sunday’s showdown will notch another exciting chapter in the Mahomes-Allen saga, one where the winner would most likely look favored upon to win the AFC Championship.

In games like these, the onus will be on the quarterback and offensive play. But with these teams being so equally dynamic, the smallest things will be the difference makers: field position, turnovers, key defensive stops.

So far Mahomes is up 2-1 in his battles with Allen. But a Buffalo win spearheaded by a game-altering Allen performance could turn the tide in the AFC, Bills history and NFL history.

A Chiefs win led by Mahomes would give the Chiefs a fourth-consecutive trip to the AFC Championship and help further establish a new norm with Mahomes and the Chiefs at the top of the conference.