Week six of the NFL season produced a sharp split between a team cruising at the top and a preseason favorite sliding toward the bottom. The Kansas City Chiefs remained unbeaten with a 22-6 win over the Los Angeles Chargers, while the Los Angeles Rams lost 18-16 at home to the Arizona Cardinals and fell to last place in the NFC West.

How did the Chiefs reach 5-0?

Patrick Mahomes reached 100 regular-season victories in his 131st start, matching a record held by Tom Brady, according to the BBC. Running back Kenneth Walker III carried for 128 yards and two touchdowns against the Chargers.

Walker, signed after the Chiefs missed last season's playoffs, now leads the league with 665 rushing yards. According to the BBC, no player has gained more on the ground in his first five games with a new team. Kansas City hosts Seattle next Sunday night.

Why are the Rams struggling?

Los Angeles entered Sunday as a 12.5-point favorite, according to NFL.com, but never led by more than three points. The Rams replaced kicker Harrison Mevis during the week with Blake Grupe, who opened the scoring and then injured a knee while tackling on the ensuing kickoff. Punter Ethan Evans handled an extra point late in the game.

Arizona's Chad Ryland kicked a career-high six field goals, the last as time expired. Coach Sean McVay blamed mistakes rather than the opponent: "We won't win a game unless we figure out how not to beat ourselves."

What does this mean for the division?

The Cardinals, who won three games last season, are now 2-0 at SoFi Stadium this year after also beating the Chargers in week one. They sit above the Rams in a division that includes the unbeaten San Francisco 49ers and the defending champion Seattle Seahawks.

FAQ

Which teams are still undefeated?

Kansas City and San Francisco are both 5-0, with the 49ers scheduled to host Washington on Monday night.

How did the Rams fall to last place?

Their loss to Arizona, combined with the 49ers' perfect start, left Los Angeles at the bottom of the NFC West with a 2-4 record.