Allen passed for 329 yards and three touchdowns for the Bills, who have the best record in the AFC.
Register now for FREE unlimited access to Reuters.com RegisterButker booted a 44-yard goal to give the Chiefs a 20-17 lead with 9:49 remaining in the fourth quarter.
Jimmy Garoppolo threw two first-half touchdown passes to Brandon Aiyuk, but also mixed in a pair of interceptions on a 29-for-41, 296-yard day.
Bengals 30, Saints 26Joe Burrow threw three touchdown passes as visiting Cincinnati came from behind in the fourth quarter to defeat New Orleans.
The two connected on a scoring strike with 9:55 left in the fourth quarter to help the Steelers snap a four-game losing skid.