KANSAS CITY, Mo. -- In many corners of their victorious locker room, the 8-0 Kansas City Chiefs claimed they were energized by being the last ones standing. Jamaal Charles said being the NFL’s last remaining undefeated team makes all the work worthwhile. Quarterback Alex Smith said it’s an honor to have opponents coming hard after them, as has been the case in recent weeks.

Their actions on the field send a much different message. The Chiefs suddenly look weary, like a team carrying a burden.

They survived again on Sunday against the Cleveland Browns, winning 23-17. But they continued their unsettling habit of letting losing teams hang around and get to the fourth quarter with a chance at victory.

The Browns fell behind 13-0 at Arrowhead Stadium only to charge back behind their new starting quarterback, Jason Campbell. Campbell was playing only because the Browns’ first choice at quarterback, Brian Hoyer, is out for the season with a knee injury and the first backup, Brandon Weeden, was so bad he was benched.

The Chiefs still had to sweat a stressful fourth quarter. Where last week, there was much joy over their ability to hold off the Houston Texans, this time the emotion was pure relief.

“These grind-it-out games, they’re tough," Chiefs coach Andy Reid said. “You work hard during training camp so you’re mentally strong enough to be able to handle things like this, and that’s what we did. We’ll continue to work hard, and I’m sure there will be other games like this where you have to grind them out."

That’s not a good look for a team having just completed the easy portion of its schedule. The Chiefs on Sunday concluded a three-game homestand against opponents who won’t be going to the playoffs. There’s something to be said for emerging with their winning streak intact, messy as things might have looked.

"The best you can be right now is 8-0, and that’s where we’re at," linebacker Derrick Johnson said. “Everybody is going to give us their best. We know that. If we can take that punch and keep rolling, that’s what we did today."

Next week, the Chiefs go back on the road for the first time in almost a month to face the Buffalo Bills. What follows certainly qualifies as a gauntlet: two games each against the Denver Broncos and San Diego Chargers, road games against the Washington Redskins and Oakland Raiders and a home game against the Indianapolis Colts.

Every last one of those opponents figures to be coming after the Chiefs, much as the Texans and Browns did the past two weeks.

“We know next week we’re going to get Buffalo’s best shot, playing up in Buffalo," Charles said. “We know they’re going to give us all they can give us."

Charles went on to say he welcomed the challenge, but his words didn’t have the proper conviction to be convincing. Their games have become a grind and, to their credit, the Chiefs have often been grittier than their opponent. They had five sacks two weeks ago in the fourth quarter against Oakland, and four in the final quarter against the Texans.

That kind of effort requires a lot of energy, and they didn’t show they had it late in the game Sunday. Maybe they’ve given too much and the tank, at least temporarily, is empty.

Again, that’s not the party line.

“Not that anybody sneaks up on anybody in this league, but when you’re the only undefeated team, I think teams have recognized how we’re playing and no question they’re coming prepared," Smith said. “We love it. You want the stages to get bigger. That’s why you put in all the work in the offseason. That’s why you do training camp. You want these opportunities. You want that honor."

That much, of course, is true. The Chiefs have lost 12 or more games in four of the past six seasons, so to get to 8-0 is beyond any of the survivors’ dreams.

That doesn’t explain how the second half looked like it meant more to the Browns, who are now 3-5. They were the ones who turned up the heat in the second half, sacking Smith five times.

“We’re not trying to be beauty queens," wide receiver Dexter McCluster said. “It’s never too close for comfort when it’s a win."

That doesn't change the fact that the Chiefs are living on the edge. Maybe they can continue happily on that way. More likely, going on the road to Buffalo, historically a graveyard for the Chiefs, or to Denver in its subsequent game on Nov. 17 will be enough to push them over the edge.

One way or the other, the Chiefs seem intent on finding out.