KANSAS CITY, Mo. – Backup running back Knile Davis returned the second-half kickoff 99 yards for a touchdown and the Kansas City Chiefs cruised to a 34-7 victory over the St. Louis Rams on Sunday at Arrowhead Stadium.

The Chiefs, 4-3 after opening the season with a pair of losses, trailed 7-0 after one quarter but scored 34 unanswered points including a pair of rushing touchdowns from Jamaal Charles, and sacked Rams quarterback Austin Davis seven times. Quarterback Alex Smith completed 24 of 28 passes for 226 yards, connecting six times with wide receiver Dwayne Bowe.

The Rams generated only 200 yards of offense, fell to 2-5 and were decimated by injuries. By the fourth quarter, only one offensive line starter was in the same position at which he opened the game and an injury-riddled secondary was minus the two safeties that started the game.

Davis led the Rams to a touchdown on the first possession of the game, rolling 65 yards on six plays capped by a 1-yard touchdown toss from Davis to tight end Lance Kendricks. The key play in the drive was a 43-yard pass play from Davis to wide receiver Kenny Britt on third-and-1.

The Chiefs tied the score with a 10-play, 53-yard drive that lapped over the end of the first quarter and start of the second. A 17-yard pass from Smith to tight end Travis Kelce took the ball to the one-yard line, setting up the score as Charles blasted through the left side.

St. Louis had a great opportunity in the second quarter when Charles fumbled and the ball was recovered by Rams defensive end William Hayes at the Chiefs 8-yard line. Two running plays netted St. Louis two yards and on third-and-goal, Davis was sacked by Chiefs safety Ron Parker for a 14-yard loss.

That setup a 38-yard field goal attempt for Zuerlein, but he pushed his kick wide right and the Chiefs escaped.

Kansas City added a 53-yard field goal from Cairo Santos with one second left in the first half, only after overcoming a false start penalty and consecutive sacks by Rams defensive end Robert Quinn to get those three points on the board and carry a 10-7 lead to intermission.

Davis, who had a 108-yard return last season against Denver, sparked Kansas City’s second-half surge with Chiefs first return score of the season. Santos added a 28-yard field goal near the mid-point of the third quarter and the Kansas City lead grew to 20-7.

A pair of fourth quarter touchdown runs — 36 yards by Charles and 3 yards from Davis – capped the scoring.

NOTES: Injuries impacted the Rams, who lost WR Brian Quick (arm) and RG Rodger Saffold (shoulder) in the first half. In the second half, C Scott Wells (elbow), LT Jake Long (knee), S Cody Davis (concussion) and S Rodney McLeod (knee) all left with injuries. … Late in the third quarter only right tackle Joe Barksdale was playing the same position in the St. Louis starting offensive line. … Chiefs starting CB Jamell Fleming in the first half with a hamstring injury. … S Ron Parker had a first quarter interception of Davis. … The normally sure-handed Chiefs had two fumbles in the first half. QB Alex Smith lost a ball that rolled out of bounds and RB Jamaal Charles fumbled. … The teams were playing for the Governor’s Cup, awarded since 1968 to the winner of any game between the Chiefs and the NFL team playing across the state in St. Louis — first the Cardinals and since 1995 with the Rams. It was the 45th preseason or regular season meeting and the Chiefs now hold a 27-16-2 edge.