KANSAS CITY, Mo - The Chiefs remained the NFL's only unbeaten team, with rookie kicker Harrison Butker's third field goal of the game lifting Kansas City to a 29-20 win over the Washington Redskins.
Butker, making his NFL debut, connected on a 43-yard field goal with four seconds remaining, breaking a 20-20 tie. Linebacker Justin Houston returned a fumble for a 13-yard touchdown on the last play of the game to account for the final margin.
Butker's 26-yard field goal in the final seconds of the third quarter tied the game at 17-17, and his 32-yard kick with 4:55 left in the fourth quarter put the Chiefs ahead 20-17.
Washington's Dustin Hopkins tied the game at 20 by making a 40-yard field goal with 47 seconds remaining before quarterback Alex Smith drove the Chiefs 50 yards in six plays for the winning score.
Rookie Kareem Hunt powered Kansas City (4-0) during its comeback from a 10-7 halftime deficit. The NFL's leading rusher collected 101 yards on 21 carries, with 78 yards coming in the second half.
Smith gave the Chiefs their first lead of the game midway through the third quarter with a 1-yard touchdown run.
Butker, making his NFL regular-season debut, connected on three second-half field goals after missing his first attempt late in the second quarter.
The Redskins (2-2) had one last chance to win the game on the final play. Washington fumbled on a quick succession of lateral on the final play, but Houston recovered the loose ball went in for the score.
Smith completed 27 of 37 passes for 293 yards and one touchdown. Redskins quarterback Kirk Cousins was 14 of 24 for 215 yards and two scores.
Washington had never won in four trips to Kansas City but had a chance to make franchise history with a halftime lead.
Cousins connected with Terrelle Pryor Sr. for a 44-yard touchdown on the Redskins' first drive. Hopkins then hit a 19-yard field on the Redskins' second drive.
Washington frustrated the Chiefs' offense much of the first half. Tight end Travis Kelce (seven receptions, 111 yards) delivered one of the lone highlights for Kansas City in the first half, hauling in a 17-yard touchdown pass from Smith with 1:54 left in the second quarter.
Butker missed a tying 46-yard field goal attempt in the final minute of the half for Kansas City. It was his first career attempt.
The Chiefs experienced a key injury on their first offensive series, losing starting right guard Laurent Duvernay-Tardif for the game with a left knee injury. Jordan Devey took over at right guard in his absence. Left tackle Eric Fisher, a game-time decision due to back spasms, was in the starting lineup. The Chiefs also were without starting center Mitch Morse, who sustained a foot sprain in Week 2.
Smith struggled behind the makeshift offensive line. He seemed to take pressure on almost every throw, with Washington tallying two sacks and five hits on Smith in the first half. Smith also scrambled from the pocket three times.
Washington sustained losses on both sides of the ball. Star cornerback Josh Norman injured his ribs in the second quarter and was ruled out for the game.
Redskins coach Jay Gruden told ESPN sideline reporter Lisa Salters at halftime that he expected Norman to be out a "couple of weeks." Norman left the game shortly after delivering a big hit on Kelce.
Washington running back Rob Kelley exited the game in the second quarter with an ankle injury. A few plays later, Redskins left tackle Trent Williams left the game with a right knee injury, but he later returned.
NOTES: Washington TE Vernon Davis had the game's longest reception, 69 yards. He finished with two catches for 89 yards. ... Redskins QB Kirk Cousins gained 38 yards on seven carries, both team-high totals. ... Four Redskins recorded one sack apiece, while the Chiefs never sacked Cousins. ... Kansas City plays the Texans in Houston on Sunday. ... Washington is headed into its bye week before a return to action Oct. 15 at home against the San Francisco 49ers.