Not just trailing, either. They were in a 17-3 hole midway through the third quarter.
They rallied down the stretch, even taking a brief lead in the fourth quarter. But a defensive collapse and their offense's inability to go the length of the field in the closing minutes led to a humiliating 24-20 defeat, one that knocked Kansas City from first place in the AFC West.
''We wanted to start off fast and we didn't play like that in the first half,'' Chiefs linebacker Josh Mauga recalled, ''and it kind of hurt us.''
That may be an understatement.
''We didn't really start the way we wanted to,'' Chiefs quarterback Alex Smith admitted. ''You know, on the road, we gave them too much momentum, it felt like.''
When asked to explain the Chiefs' slow start, running back Jamaal Charles was stumped.
''I don't know, you know? Some games are just like that,'' he said. ''You learn from those games. Hopefully we'll learn from it and move on and come back next week against Denver.''
Yes, the Chiefs get their bitter division rival at Arrowhead Stadium on Sunday night, and with them a prime opportunity to move back into a tie atop the AFC West. But unless they are able to solve a troubling trend of slow starts, Peyton Manning and the Broncos could bury them early.
The Chiefs are 5-0 when leading at halftime. They're 2-4 in all other games.
''We come back home and then we've got another big division game, and we are about to handle this the right way,'' Smith said. ''We can regroup and get it together.''
Just how do you get it together, though? How do you fix slow starts?
After all, it's not a tangible problem, something that can be fixed with playcalling alone. It doesn't come down to personnel groups, necessarily, or the scheme for the week.
Often, it involves all of those things and more.
In their opener against Tennessee, the Chiefs trailed 10-3 at halftime. They were behind 23-3 by the fourth quarter, when they finally found traction. The result was still a 26-10 loss, one that is even more frustrating now that Kansas City has clawed back into playoff contention.
A few weeks ago in Buffalo, the problem popped up again.
Kansas City trailed 10-3 at halftime and 13-3 after three quarters, finally coming alive when the game was coming down the stretch. The Chiefs scored two fourth-quarter touchdowns, their defense shut the Bills out and the result was a confidence-building 17-13 victory.
The result was better. The way the Chiefs got there was a bit disappointing.
Andy Reid has experience just about everything over the course of his coaching career, and even the Chiefs' boss has yet to put his finger on the solution to the slow starts.
''Well, I've got to make sure that I dial up plays that will help us with that. If you have an opportunity then we've got to execute when given the opportunity,'' he said. ''It hits all of us and defensively the same thing. There are things you can do as a coach with play calls and then the guys have to execute; we're all in it together that way.''
Reid shouldered much of the blame for the flop in Oakland, and admitted that ''we weren't as well coordinated as we needed to be.'' But he also said the Chiefs failed to grasp the opportunities that were presented, and that responsibility falls on the players.
''You've got to stay on and execute. That's one area on both sides of the ball we can do better at it. We didn't do a great job there,'' Reid said. ''I didn't feel it was a letdown; the guys didn't work hard and all that. It was one of those deals.''
One of those deals the Chiefs are trying hard to resolve by Sunday night.
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