KANSAS CITY, Mo. — Only a bye week, it seems, can stop the Kansas City Chiefs.

The prohibitive AFC West favorites could not do it in the opener.

Nor could the dreaded short week of practice before a road game.

Even Matt Cassel was incapable Sunday of derailing momentum.

Now one of the NFL's biggest surprises will try not to cool off while sitting idle. This after the Chiefs actually got their offense untracked and whipped San Francisco's vastly overrated Niners, 31-10.

New Arrowhead? Please. More like new team.

Seriously. Is Kansas City for real? The debate will at least extend until Oct. 10, when the Chiefs play next, at Indianapolis.

"We're still trying to figure out what everybody's top end is," KC coach Todd Haley said. "It's encouraging. It appears to me we have a number of guys who aren't going to be willing to accept bars being set for them."

Unlike the first two victories, which included a fortuitous dose of dumb luck, the beatdown of the 49ers included for-real qualities with a touch of well-timed trickery.

Yet the touchdown generated off a reverse pass Cassel threw as a receiver out of the Wildcat formation — call it an AFL throwback to go with the game-long tribute to longtime broadcaster Bill Grigsby — wasn't even the Chiefs' best play.

That belonged to Tony the tight end. No, not that Tony. Another one. Rookie by the name of Moeaki. His leaping one-handed stab in the back of the end zone with more than 16 minutes remaining removed any and all mystery.

Here's the unreal symmetry: It's Week 3, the Chiefs are coming off the worst three years in franchise history and they're icing wins in the third quarter.

Oh, and they're 3-0. The buzz may not be enough to justify those club-level seats priced at more than $200 a game, but at this rate, that's going to be the only vacant area in Arrowhead.

Sure, it's early. But the Chiefs covered great. They stuffed the Niners' only rusher (how predictable is that?), Frank Gore. And the pocket collapsed frequently, thanks in large part to Tamba Hali.

And those are all defensive attributes. By halftime, the Chiefs' 250 yards of offense was a mere 4.5 yards off their season average. Maybe it's grading on a generous curve to count burst plays as gains of 15 yards or more, but do so and the Chiefs managed 15 of them by five different players.

All of them took directions from Cassel, who showed a serious uptick in confidence. He threw for 250 yards and three touchdowns. One score, a 31-yarder showcasing Dexter McCluster's speed, came on the first pass following Cassel's only interception.

The dazzler was the 45-yard trick pass that went over the top to Dwayne Bowe with 9:21 left in the third quarter.

"We had a lot of production before that, but that definitely gave us a jolt of energy and you saw it down the sideline," Cassel said. "From there, we were kind of having a party out there. Everything was going well."

Even the risky stuff. The Chiefs shuffled out their punt team to convert a fourth-and-1 from midfield to start the second quarter. They would have executed an onside recovery, too, had rookie Eric Berry not been ruled offside.

The bold imagination "just gives us confidence," Cassel said.

"In the huddle, you can see it in the linemen's eyes, and the running backs. They just get energized. They get excited from being aggressive and making big plays downfield. That's what it's all about, being excited about what you're doing."

The only thing not to like is the bye week. Yet Haley is "grateful" for the break. He's a coach. Everything can be better. Practice makes it so.

"We are a team in transition," Haley reminded everyone. "We've been a team that hasn't won a lot of games in a number of years ... one of the great teams in history. But the Kansas City Chiefs have not accomplished what the purpose of having that kind of team is. We're in the process of changing that."

Kevin Haskin can be reached at (785) 295-1159 or kevin.haskin@cjonline.com.