KANSAS CITY, Mo. _ The Steelers delivered a knockout blow to the last remaining undefeated NFL team, holding on for a 19-13 victory.
After losing two of the past three games, the Steelers smothered Kansas City's offense in the first half and held their breath as the Chiefs mounted a comeback in the fourth quarter.
They raised their record to 4-2, alone in first place in the AFC North Division. Kansas City dropped to 5-1.
The Chiefs were poised on the Steelers' 40 when James Harrison, on third down, sacked Alex Smith back to the 48 with 58 seconds to go.
Le'Veon Bell rushed for 179 yards and a touchdown on 32 carries.
Kansas City scored their first touchdown with 6:13 left in the game on a 57-yard touchdown pass from Alex Smith to De'Anthony Thomas.
That cut the Steelers' lead to 12-10 but their offense responded in kind.
On third-and-two from their 49 on the next series, Ben Roethlisberger uncorked a medium-range pass toward the left sideline. Cornerback Phillip Gaines tipped the ball right into the hands of Antonio Brown at the 34. Brown then ran into the endzone to complete a 51-yard touchdown.
That put the Steelers back on top by two scores, 19-10.
However, neither were the Chiefs through. Two deep passes on their next series gave them a first down at the Steelers' 15 but they could gain no more and rookie Harrison Butker kicked a 33-yard field goal.
The Steelers now led 19-13 with 2:17 left and that's how it ended.
The third quarter was scoreless but the Chiefs had their biggest play of the game to put the ball at the Steelers 12 on a 37-yard pass from Alex Smith to Kareem Hunt plus a 12-yard penalty against Mike Mitchell for roughing Smith.
However, as the fourth quarter started, the Steelers' defense held again. The Chiefs worked their way to a third down at the three. Hunt got a yard and then Sean Davis broke up a pass in the end zone on fourth down.
The Steelers used a stifling defense and mixed up the run and the pass on offense to take a 12-3 halftime lead.
They scored three different ways in the half _ on a safety, a Bell 3-yard run and Chris Boswell's 24-yard field goal. Their defense held Kansas City to one first down in the first two quarters.
The Chiefs managed just 6 yards in total offense in the first half to 232 for the Steelers.
Unlike last week when they failed to run much on the NFL's worst run defense, the Steelers came out pounding against the Chiefs.
Bell ran 17 times for 99 yards in the first half one week after he ran 15 times for 47 yards in the Steelers' upset loss to Jacksonville at home. He ran eight times for 64 yards on a 75-yard drive that ended with him powering up the middle for a 3-yard touchdown on the first play of the second quarter.
That gave the Steelers a 9-3 lead and also gave Bell 71 yards rushing in one quarter and one play.
Bell was out of the game when Ben Roethlisberger's pass for Antonio Brown was intercepted by cornerback Marcus Peters and returned 16 yards to the Steelers' 48 on their next series.
KC could get nothing on that drive _ indeed they had no first downs to that point _ and punted to the one.
The Steelers then mounted an impressive drive that ended unimpressively. They moved 93 yards on 12 plays. They had a first down at the two. But Roethlisberger lined up in the shotgun from there on the next three plays. He threw incomplete, Bell lost four on a deep handoff and a third-down pass did not connect.
Chris Boswell kicked a 24-yard field goal to end that 12-play, 93 yard drive to boost the Steelers' lead to 12-3.
The Chiefs led 3-2 at the end of the first quarter.
A promising opening drive by the Steelers reached Kansas City's 34 but on third-and-three, linebacker Dee Ford got around Alejandro Villanueva to sack Roethlisberger, ending that drive.
But then they scored on Kansas City's first drive when a high snap in the shotgun from the nine yardline by backup center Zach Fulton sailed over quarterback Alex Smith's head and through the end zone for a safety.
The Steelers led 2-0.
That did not last long thanks to a gaffe on the next play by Brown. Dustin Colquit punted on the free kick from the 20 and Brown let it bounce. However, the free kick is like a kickoff so it was a live ball and the Chiefs recovered at the Steelers' 32.
The Steelers defense held and Butker kicked a 46-yard field goal to put KC up 3-2.
