By Lynette Rice
Updated November 01, 2010 at 05:21 PM EDT

Image Credit: Michael Yarish/CBSSerious competition from NFL football on NBC and Game 4 of the World Series on Fox wreaked havoc on on CBS’ The Amazing Race and Undercover Boss. The competition show at 8 p.m. averaged 2.9 rating/7 share in 18-49 — down 17% from last week and also a season low, according to early estimates from Nielsen. It averaged 9.1 million. At 9, Boss earned a 2.9/7 — down 10% to its lowest-rated telecast ever. The sophomore show averaged 10.3 million. CSI: Miami at 10, meanwhile earned a 2.6/7 and averaged 9.8 million.

Each 18-49 ratings point represents 1.3 million.

But hey, it’s not so easy to go up against football and baseball. Fox ruled the night in viewers (15.2 million) but NBC won the night in the 18-49 demographic (5.2/14) because of the matchup between the last two Super Bowl victors, the Steelers and the Saints. The game itself averaged a 6.6/17 in the demographic. Fox came in second in the demo (4.7/13) because Game 4 earned a 4.3 rating. CBS was third with a 2.4/7 and 10.0 million eyeball.s

As for ABC, which finished fourth with a 2.2/6 and 7.9 million, Extreme Makeover: Home Edition finished with a 1.8/5 and 6.6 million viewers, followed by Desperate Housewives (3.5/9, 10.9 million) and Brothers & Sisters (2.3/6, 8.1 million).