Tony Moeaki catch, Chiefs running game impressive in win over 49ers Sunday(VIDEO)

It's hard to say which is more surprising — undefeated Kansas City or winless San Francisco.

Three weeks into the season and the Chiefs (3-0) are roughly a third of the way toward their combined victory total from the previous three seasons after a 31-10 rout of the 49ers on Sunday.

It would have been 31-3 if the 49ers hadn't scored on Alex Smith's 12-yard touchdown pass to Josh Morgan on the final play from scrimmage.

Adding to the angst 49ers fans are sure to feel, Morgan went down on that meaningless play and was slow to get up.

"I think the guy hit him in the back of the leg and I think his knee got a little banged up on that," said San Francisco coach Mike Singletary.

Matt Cassel threw three touchdown passes and Tamba Hali got three of the Chiefs' five sacks. The Chiefs haven't been 3-0 since 2003, when they started 9-0. Now they take their bye week before successive road trips to Indianapolis and Houston.

"We just have to keep it going," said cornerback Brandon Flowers, whose interception was followed by Cassel's 31-yard TD pass to Dexter McCluster. "We can't settle for 3-0. We've got a bye week, we have time to prepare for our next opponent."

This game bore no resemblance to the sloppy opening night victory over San Diego or the win over Cleveland last week when the offense did not score a touchdown.

"I'm proud of the guys," said head coach Todd Haley, in his second season. "They're just working hard every day to get a little better."

Cassel was 16 for 27 for 250 yards and tossed a perfect 45-yard strike to a wide-open Dwayne Bowe off a fake end-around.

Rookie tight end Tony Moeaki put Kansas City on top 24-3 late in the third with a great falling down, one-handed catch of Cassel's 18-yard pass.

"It was exciting," the rookie tight end said. "Matt just threw a really great ball and put it in a great spot. I just tried to make the catch."

It's the second time in three games San Francisco has been dominated, which is sure to cause disquiet among fans who expected the 49ers to contend.

Singletary hinted at personnel changes.

"Right now, what we are going to do is get back and look at the film and hold off on making any changes until we look at the film and go from there," he said. "We will look at the film and see what is there and make decisions accordingly."

Jamaal Charles rushed for 97 yards for the Chiefs and Thomas Jones added 95, including a 3-yard scoring run that made it 31-3 with 3:27 left. KC's 457 total yards were the most since gaining 524 in the final game last season.

The 49ers wound up with 251 total yards, which included 53 yards on their final two plays.

"We were pretty ineffective the entire game," Smith said. "I don't know if there is anything to point to. I think it is everything. We were pretty inept all the way around, throwing the ball, running the ball, protecting, penalties, it was all in there."