KANSAS CITY, Mo. (AP) — The way Indianapolis handled the Kansas City Chiefs on Sunday night sent a jolt through the NFL, whether it was dominating the line of scrimmage or shutting down Patrick Mahomes and Co. on defense.

The one place the shock didn’t reverberate? The visiting locker room in Arrowhead Stadium.

“The one emotion we were not feeling is shock. I can’t even explain it,” Colts coach Frank Reich said after the 19-13 victory. “The way guys were walking down the hallway, it was ‘We’re not going to be denied. We have to get on track. We’ve got to do it.’ I just knew it was real. I felt it all week.

“There was just an air of confidence and belief that we would do what we did today.”

Marlon Mack ran for 132 yards , and ageless kicker Adam Vinatieri knocked through four field goals, as the Colts atoned ever-so-slightly for a January playoff defeat inside the same stadium.

Asked what the message was pregame, longtime Chiefs linebacker-turned-Colts defensive end Justin Houston replied: “To come out here and play our game. To leave it out there every snap, to play with your heart, play with your soul. And I think we did that tonight.”

The Colts (3-2) allowed points on the Chiefs’ first two possessions before shutting them out until Harrison Butker’s field goal with 1:16 to go. Indianapolis recovered the onside kick without any issue and ran out the clock to celebrate a big win heading into its bye.

Jacoby Brissett beats Damien Wilson into the end zone.
Jacoby Brissett beats Damien Wilson into the end zone.AP

Mahomes threw for 321 yards and a touchdown, and the Chiefs (4-1) had just 36 yards rushing despite getting top running back Damien Williams back from an injury, all while watching their record streak of 22 straight games scoring at least 26 points come to a crashing conclusion.

“Penalties are really what hurt us today,” said Chiefs coach Andy Reid, whose team was flagged 11 times for 125 yards. “You get things going, all of a sudden you’re going backward, and it’s tough in this league to do that against a good team and win.”

In an air-it-out era of the NFL, the Colts also won by dominating the line of scrimmage.

On offense, their big line bruised a Kansas City defensive front that lost Chris Jones and Xavier Williams to injuries. That created big holes for Mack and plenty of time for Jacoby Brissett, who threw for 151 yards while running for the Colts’ only touchdown.

On defense, the Colts spent most of the night in the Kansas City backfield, plugging up holes in the running game and relentlessly pressuring the reigning league MVP on passing downs.

Mahomes was sacked four times and hit plenty more. At one point in the second half, Cam Erving was pushed so far into Mahomes’ face that the backup left tackle stepped on his quarterback’s ankle, leaving Mahomes to hobble to the sideline when Kansas City was forced to punt.

“In this league, the margin of error is tiny,” said Mahomes, who dismissed the seriousness of his injury. “If you’re not executing at a high level you’re going to lose.’”

The Colts and Chiefs mostly played to a first-half stalemate, but the second of Vinatieri’s four field goals made it 13-10 at the break. The real winners were the officials, who finally got to rest the arms that they used to throw flags for the first 30 minutes.

The Chiefs’ prolific offense continued to sputter in the second half, and Brissett and the Colts essentially played a game of keep-away throughout the third quarter and into the fourth.

“You don’t need a large playbook to convert third-and-1,” Chiefs defensive end Frank Clark said.

The Colts used 8:34 off the clock to move a mere 35 yards and set up Vinatieri’s next field goal. Then, when the Chiefs failed to convert fourth-and-1 at their own 34, Indianapolis got another field goal from Vinatieri with 2:30 to go to make it a two-possession game.

“You could just tell they were hungry. They were hungry all week,” Reich said. “I know that’s not uncommon, but there was something different about this week. I could feel it. It was palpable. We just walked in here with a lot of confidence. Last night in our meetings, I can’t even explain what happened in our meetings last night. There was just a feeling amongst the team when we walked into this stadium.”