NBC has extended its dominance of the summer primetime Nielsens with an Aug. 18-24 victory that’s the Peacock’s easiest in nine weeks.

In summer-long figures, NBC now leads its closest competitor, ABC, by 5 shares in adults 18-49, and has achieved first-place 18-49 averages on six nights of the week (Saturday is the lone exception, though NBC needed NBA boosts on Friday and Sunday to maintain first on those nights).

Since the close of the May sweeps, NBC has averaged a 4.8/16 in adults 18-49, putting it far ahead of second-placer ABC, 3.5/11, as well as Fox, 3.2/11 and CBS, 3.0/10.

Aug. 18-24 scores in that demo were: NBC, a 4.8 rating, 15 share (down in rating by 2% vs. results for the same week last year); ABC, 3.8/12 (down 3%); CBS, 3.3/10 (down 3%); Fox, 3.1/10 (down 3%); UPN, 1.7/5 (up 21%); WB, 1.2/4 (down 8%).

Monday

On Monday, Aug. 25, NBC’s “The Beast, Part 2″ (9.0 rating, 15 share) devoured the competition and finished with the highest 18-49 average of any multiple-parter aired this summer (5.4/15), even topping Fox’s firstrun “Intensity.”

As is occurring with NBC’s Wednesday film, this Monday movie success builds a case against the Peacock’s sitcom-heavy fall strategy.

The combo of “Dateline NBC” (9.6/17) at 8 p.m. and the 9-10 p.m. hour of “Beast, Part 2″ improved by a healthy 20% on the nine-week adults 18-49 average of NBC’s Monday “Must-She” comedy lineup.

CBS also benefited from NBC’s schedule change. The CBS comedies immediately surged to their best numbers (an average 7.8/13) since June 9, the week before NBC’s sitcom lineup hit the schedule.

UPN’s fall Monday schedule premiered solidly with an average 5.2/9 in the metered markets (see separate story).

Sunday

CBS stunned the competition with an outright Sunday victory in adults 18-49 for just the second time in 16 months. “60 Minutes” and “The Man Without a Face” won their slots in that demo. Fox, the usual Sunday 18-49 winner, still had the slightly higher 7-10 p.m. “common time” average. It was CBS’ highest Sunday 18-49 rating since May 18.

NBC got a good Sunday start from “Men Behaving Badly,” which improved by 5% on its 18-49 lead-in from “3rd Rock From the Sun.”

It’s NBC’s best build by a sitcom in that post-“3rd Rock” slot since June 15. “Men” becomes the NBC Sunday cornerstone this fall when “3rd Rock” moves to Wednesdays.

NBC was still a lackluster third that hour in adults 18-49, as “3rd Rock” continues to roll downhill over the summer. Last Sunday, “Rock” landed 5 shares behind “The Simpsons” in adults 18-49.

Saturday

NBC edged Fox’s football to win Saturday among adults 18-49.

“The Pretender” beat slot rival “Dr. Quinn” by more than 50% in that demo, with NBC’s best slot score since May 17 (“Bloopers”). CBS took the night in homes.

In its second Saturday airing, “PrimeTime Live” generated the first evidence that a newsmag might turn around the night for ABC. “PTL” improved by 14% in adults 18-49 over its first try and reported ABC’s best average in that slot in four weeks.

Fox football slipped 10% in adults 18-49 vs. the comparable year-ago Green Bay-Indianapolis gridcast, due in part to a 73% clearance for its first hour.

For all primetime preseason telecasts this summer, Fox dropped by 6% in homes compared with last year’s average and ABC declined by 11%.

Friday

Despite the highest-rated Friday “Dateline NBC” since April 11, ABC held off NBC for a 10th-straight Friday win (including two ties in adults 18-49).

Low clearances due to local NFL coverage hurt all the nets, none more than Fox. “Roar” got laryngitis in its first Friday try, croaking out the lowest rating ever in that slot in Fox’s nearly seven years of Friday programming. The record-low “Roar” was cleared in just 87% of the country.

Thursday

NBC took the night by 12 shares in adults 18-49, despite ABC’s best Thursday 10-11 p.m. results since May 1 from the rerun John Stossel newspec “Freeloaders.”

Wednesday

ABC maintained its Wednesday advantage as “Spin City” continued to look comfortable in its “Drew Carey” hammock, up 7% over “Carey’s” 18-49 lead-in.

CBS’ “Miss Teen USA” displayed its most buxom Nielsens in three years. Male viewers generated much of the growth — with gains over year-ago men 18-49 and 25-54 figures of 17% and 22%, respectively.

Tuesday

NBC won the night, as its two recently transferred sitcoms continue to veer in opposite directions. “NewsRadio” built by 2% on its 18-49 lead-in from “Mad About You” while “Just Shoot Me” fell 14% below its lead-in from “Frasier.”

ABC’s “Grace Under Fire” is putting up Tuesday numbers that lend strong support for its renewal as a fall backup. “Grace” is averaging a 21% improvement on its 18-49 lead-in from “Roseanne,” while canceled slot predecessor “Life’s Work” averaged a meeker 13% build earlier this summer.

“JAG” filed CBS’ best regular-programming adults 18-49 rating in that slot in five months.

Monday

“Dateline NBC” dominated Aug. 18 results with the highest rating for any primetime telecast since the NBA Finals (Daily Variety, Aug. 20).

Each rating point represents an estimated 970,000 households, or 1% of the country’s TV homes. The share is the same sort of percentage, except that it’s measured against only the households in which TV is being watched during the timeslot involved.

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