Three story lines

Rare territory. The Chiefs can get off to their first 3-0 start since 2003 by beating the 49ers. More important, it should give Kansas City some staying power in the AFC West race. After playing San Francisco, the Chiefs face a difficult two-game road trip to Indianapolis and Houston.

Getting off zero. The 49ers are fortunate to be playing in the NFLâ€™s weakest division, but still canâ€™t afford to fall too far behind in the NFC West. The schedule sends the 49ers to Atlanta next week, so theyâ€™re looking at a potential 0-4 start unless they can find a way to win in Kansas City.

Passing unfancy. The Chiefs have been winning without getting much help from the passing game. It will be difficult for that to continue without some improvement from quarterback Matt Cassel. The Chiefs have just one pass play of more than 20 yards.

Three key Chiefs

S Eric Berry. A first-round draft pick this year, Berry is having a major impact on what appears to be an improved run defense. Berry had a couple of tackles for losses in last weekâ€™s game against Cleveland. He has been quick to bite on the play-fake, so look for the 49ers to try to burn Berry that way.

KR Javier Arenas. With the Chiefs struggling to score points on offense, they need touchdowns or at least field position from their special teams. Arenas and Dexter McCluster, who handles some of the returns, are capable of providing help.

TE Tony Moeaki. This rookie leads the Chiefs in receptions. He had a touchdown in the opener and two key third-down catches last week. Moeaki is not only effective with the short and intermediate routes, but has the speed to beat coverage down the field.

Three key 49ers

TE Delanie Walker. Heâ€™s overshadowed by Vernon Davis, but heâ€™s an excellent receiver and route runner. When both he and Davis are on the field, it will present all sorts of matchup issues for the Chiefs, who have had trouble with tight ends this season.

NT Aubrayo Franklin. Franklin has more than 30 pounds on Chiefs center Casey Wiegmann, who tends to struggle against much larger and more physical opponents. If Franklin controls this battle, it ruins Kansas Cityâ€™s plan to run the ball and keep it away from a more potent San Francisco offense.

LB NaVorro Bowman. A rookie, Bowman replaced the injured Takeo Spikes on Monday during the Saints. In Moeaki and McCluster, the Chiefs have some weapons in the intermediate passing game who could make things tough for Bowman.

Bottom line

The 49ers have the weapons to win a scoring war, so the Chiefs will need to keep points to a minimum if theyâ€™re to win. With Berry, linebacker Derrick Johnson and end Glenn Dorsey playing outstanding run defense, the Chiefs are positioned to make things difficult for Frank Gore and the San Francisco running game. But the Chiefs, with inexperience at safety, are allowing a lot of big pass plays. So Kansas City will need to be more productive than it has been on offense to win this game. Chiefs 20, 49ers 17.