Sean Smith returned an interception 100 yards for a touchdown and Tamba Hali scored on an 11-yard fumble return in a 23-13 win over the Buffalo Bills.

Despite giving up a season-worst 470 yards to a Bills offense that was led by undrafted rookie Jeff Tuel, making his first career start as quarterback, the Chiefs remain the NFL’s only undefeated team at 9-0.

The Chiefs held another team to 17 points or fewer for the ninth straight time — matching the NFL record set by the Atlanta Falcons in 1977.

Buffalo had the edge in yards and first downs (25-15), and ran 23 more plays than Kansas City.

The Chiefs’ offense will continue to be scrutinized as Alex Smith finished 19 of 29 for 124 yards passing. Running back Jamaal Charles had 90 yards rushing and was held under 100 yards from scrimmage for the first time this season, adding only six receiving yards.