The Kansas City Chiefs (8-0) relied on their stellar defense to defeat the Buffalo Bills (3-5) 23-13, to remain the only undefeated team in the NFL.

 

On a day when their offense failed to score a TD, the Chiefs got big plays from DB Sean Smith, who returned an INT 100-yards for a TD, and LB Tamba Hali, who scooped up a fumble and rambled for an 11-yard TD.

 

The Bills were forced to start third-string QB Jeff Tuel, who got the game started with a 59-yard TD to WR Marquise Goodwin, but they were unable to keep the momentum going.

 

What is the reason for this incredible winning streak?