KANSAS CITY - The Kansas City Chiefs did to themselves Sunday night what rivals have been trying to do for the better part of two years: They slowed themselves down.
In what became a 19-13 loss to the Indianapolis Colts, the first time Patrick Mahomes and his teammates failed to score at least 26 points in 22 games, the Chiefs committed 11 penalties for a whopping 125 yards to spoil a nip-and-tuck game that wasn't decided until the fourth quarter.
"We kind of shot ourselves in the foot," coach Andy Reid said. "Drove right down the field, penalty set you back, had a turnover on a big gain. But penalties are what really hurt us. You get things going and all of a sudden you're going backward."
It wasn't the first time flags have been an issue for the Chiefs.
They were penalized seven times last week in Detroit, and they were flagged 10 times for 114 yards earlier this season in Oakland. In fact, the Chiefs (4-1) have accumulated the fourth-most penalty yards in the NFL through the first five weeks of the season.
Against the Colts, the penalties came at especially damaging times.
On the opening drive, a holding call on Andrew Wylie and a false start on Travis Kelce derailed a promising drive and forced Kansas City to kick a field goal. Later in the first half, Bashaud Breeland was flagged for a 53-yard pass interference penalty that led to a field goal for Indianapolis, and the Chiefs cornerback was hit with two more defensive holding penalties before halftime.
Early in the fourth quarter, with the outcome still hanging in the balance, wide receiver Demarcus Robinson was flagged for a facemask on first down. That put the Chiefs in a first-and-20 situation, and a sack and run that went nowhere put them at third-and-28 from their own 7-yard line.
The Chiefs picked up 27 yards to set up fourth-and-1, but they were stuffed on the conversion try and gave the ball to Indianapolis. Adam Vinatieri's fourth field goal moments later made it a two-score game, and the Chiefs ultimately ran out of time to come all the way back.
"We were just really killing ourselves as far as penalties," said Mahomes, who threw for 321 yards and a touchdown - modest and underwhelming by his measure. "I feel like we'd have a good play call and had an opportunity to execute and we just didn't get it, and that showed the whole game."
As the Chiefs prepare to face the Texans on Sunday, here are some other takeaways from what turned out to be a forgettable night for them at Arrowhead Stadium:
Sammy Watkins (hamstring) left in the first quarter and Tyreek Hill (collarbone) was inactive again, leaving Kansas City without its top two targets in the passing game.
Yet Mahomes keeps making the backups look like stars, this time finding Byron Pringle six times for 103 yards and a touchdown.
The Chiefs' run defense was abysmal again. Marlon Mack ran for 132 yards and the Colts piled up 180 as a team, and Kansas City is now allowing 155.8 yards per game on the ground.
It's also giving up 5.3 on each attempt, second-worst in the NFL behind only Jacksonville.
Free safety Tyrann Mathieu finally looked like the big-name signing he was expected to be in free agency, picking off his first pass of the season and making several big stops in the run game.
He also played a crucial role directing the defense when LB Anthony Hitchens left with an injury.
Everyone on the offensive and defensive lines struggled. The Chiefs were manhandled up front by the Colts, who ran the ball at will while holding the Kansas City offense to 36 yards rushing.
Watkins (hamstring), who left after the first series against Indianapolis, and Hill (collarbone) are questionable heading into this week. Wylie (ankle), Hitchens (groin) and DTs Xavier Williams (ankle) and Chris Jones (groin) also left the game and did not return.
Mahomes was hobbled after fill-in LT Cam Erving stepped on his ankle during the second half, but the reigning league MVP dismissed any notion that he would be slowed in practice this week.
37:15 is the amount of time Indianapolis had possession Sunday.
The Colts' ability to run the ball helped them control the game, leaving the Chiefs' potent offense with it for just 22:45.
The Chiefs' defense gets another big test Sunday against the Texans.
Deshaun Watson threw for 426 yards and five scores as Houston embarrassed the Falcons 53-32 during the weekend.