The Chiefs moved to 7-0 for the season courtesy of a 17-16 win over the Houston Texans yesterday, with the Denver Broncos' defeat later in the day meaning that Reid's side are now the only remaining unbeaten team in the NFL.
Kansas City have the stingiest defense in the league so far this season having conceded just 81 points, and Reid believes that their success has been built upon that.
"You know as well as I do you win with great defences. That's how it rolls. You can't be successful like we are without a great defence," Reid told The AP.
The Chiefs, who have now made their best start to a season for a decade, will face the Cleveland Browns in their next game on Sunday.