NEW YORK – CBS claimed a “sweeps” month victory among youthful viewers for the first time since 1980 – a milestone even the network’s top executive never thought he’d see.

With two days to go, CBS had a comfortable lead among viewers ages 18 to 49 during November, one of four months where Nielsen Media Research ratings are used to set local advertising rates. ABC and NBC were fighting for second.

CBS has been the most popular network among all viewers for the past few years, but the 18-to-49-year-old demographic is the industry’s chief currency. Advertisers pay a premium for youth and CBS’s generally older audience has been a handicap.

“We are about to accomplish something that many thought was impossible for this network,” said CBS Chairman Leslie Moonves.

That included himself when he started in 1995, he conceded. Moonves’ fortunes have risen with the network; he’s now co-chief executive of CBS’ parent company Viacom.

Moonves couldn’t resist a little crowing. In a conference call with reporters, he read old, sarcastic quotes about CBS’ geriatric audience. Two of them were uttered by NBC executives.

“We put those quotes on our locker room wall and it served us very well,” he said.

To put the ratings victory in perspective, CBS’ schedule included “The Waltons,” “Dallas” and “M*A*S*H” the last time it happened.