The Kansas City Chiefs (4-1) and Buffalo Bills (4-1) will each be looking to rebound after suffering their first loss of the season in Week 5.


And this showdown in Buffalo is a good one between two AFC postseason teams in 2019.


The Chiefs enter the game ranked third in total offense (407.2 yards per game) in the NFL, while the Bills rank fifth (401.8). The Chiefs also rank fourth in passing (287.8 yards per game) and the Bills boast the league's second-best aerial attack (308).


Monday's matchup is the 46th time the two teams will square off, and the Bills hold a 24-20-1 edge in the all-time series.


The last time the Chiefs and Bills met was in 2017, a game the Bills won 16-10. Before that meeting, the Chiefs had won three straight games in the series and have outscored Buffalo 80-64 in the past four contests between the two.


Here are some key areas to monitor for the Chiefs as the team seeks to improve to 5-1 on the season.


PROTECT THE FRANCHISE


Chiefs quarterback Patrick Mahomes produced 340 yards passing and two touchdowns with an interception last week, but he fell victim to the sack three times and the Raiders totaled five quarterback hits.


And there were times as the game progressed that Mahomes probably left the pocket sooner than he wanted.


"They did a good job with their game plan of covering the guys I want to go to and getting some pressure," Mahomes said Thursday. "But I also bailed on the pocket sometimes, and I ran out of the pocket sometimes so it's a combination of a lot of things."


Whatever the issues were, the Chiefs offensive line knows they need to do a better job in protection, especially with left guard Kelechi Osemele missing with torn tendons in both knees.


Veteran Mike Remmers, who filled in for Osemele against the Raiders, now has the job at left guard, and he believes the problems won't linger.


"I think everything that we did negatively is correctable," Remmers said. "Little technique things here and there that in about 30 minutes, I'm going to go onto the field and work on myself. I've got to be better. Everyone individually and as a group has things to improve on, and that's what our main focus is today."


Giving Mahomes time in the pocket should pay off handsomely for wide receiver Tyreek Hill and tight end Travis Kelce against the Bills' 24th-ranked pass defense (263.2 yards allowed per game).


As Mahomes goes, especially with a clean pocket, so goes the Chiefs offense.


MAKE ALLEN UNCOMFORTABLE


On the opposite side of protecting Mahomes, the Chiefs need to do a better job of getting to the opposing quarterback in Week 6.


Despite having defensive tackle Chris Jones and defensive end Frank Clark, who make up one of the NFL's best pass rush duos, the Chiefs managed just one sack and four quarterback hits on Raiders quarterback Derek Carr.


Bills quarterback Josh Allen is mobile, so that presents another issue. But the Titans harassed Allen in Week 5 en route to Allen throwing for a season-low 263 yards and a season-high two interceptions in the Bills' 42-16 loss.


The Chiefs' defense is angry after last week's defeat, which saw the Raiders produce seven big plays (defined as 20 yards or more). Six of the big plays came through the air, including touchdown passes of 72 and 59 yards, with Carr sitting comfortably in the pocket.


A repeat can't happen against Allen, who possesses a big arm and would like nothing more than having time to pick apart the Chiefs secondary.


CONTAIN THREE-HEADED WR


Buffalo's trio of wideouts is arguably the toughest group the Chiefs have faced through the first five games of the season.


Stefon Diggs is Buffalo's clear No. 1 receiving threat, and he paces the Bills with 36 catches for 509 yards and two touchdowns on 51 targets. John Brown, who appears on track to return to the lineup after missing Week 5 with a knee injury, provides the speed and deep threat, while veteran Cole Beasley is among the NFL's best slot receivers.


Playing cornerback at any level means the player must possess the mental toughness to move on from either bad plays or bad games.


Against the Bills, cornerbacks Charvarius Ward, Bashaud Breeland and Rashad Fenton must show no lingering effects from the previous week's aerial bombardment at the hands of Las Vegas.


To do otherwise could open the door to big games from Diggs, Brown or Beasley.


STOP THE RUN


The Bills haven't fully committed to the run through five games this season, totaling 122 attempts, and rank 28th in the league (93.8 yards rushing per game).


But Buffalo might shift gears if they go off paper alone.


The Chiefs enter the game ranked a dismal 29th in the league, allowing 157.6 yards per game and 5 yards per carry, and come off a game where Raiders running back Josh Jacobs totaled 85 yards (77 rushing) and two touchdowns.


Buffalo running back Devin Singletary, who has 238 yards rushing and a touchdown entering Week 6, has been kept in check this season, and the Chiefs don't want to be the team to allow him to bust loose.


Additionally, if the Chiefs can stop the run early and often, the door opens wide for the pass rush to get after Allen and not place the cornerbacks on an island against the Bills' receiving group.