FOR the first time since before 9/11, CBS’ nightly newscast has gotten out of the ratings cellar.

Last week, the Bob Schieffer-anchored news barely beat out ABC News, which has been unsteady since losing longtime anchor Peter Jennings to cancer.

“The CBS Evening News” edged out ABC’s “World News Tonight” last week by just 80,000 viewers (7.39 million for CBS versus 7.31 million for ABC).

Obviously, the win raises uncomfortable questions for CBS about why it hired Katie Couric (for $15 million a year) when the network appears to have found near-instant success with Schieffer, who is 69.

“If Bob was at a different point in his career and wanted to continue, it’d be great,” says CBS News chief Sean McManus. “But he made it very clear that he would keep the anchor chair for as long as we needed him, but he really wanted to spend more time with [wife] Pat and to ease into – not retirement – but slowing down.”

Couric is set to start on CBS Sept. 5.

The ratings bump “is satisfying, but I’m very much putting it in perspective,” McManus says. “It’s just one week and a relatively small step . . . But it gives us some really good momentum going into September.”

NBC contines to be the top rated nightly news show. But CBS has not been ranked No. 2 since Aug. 3, 2001.

Since Dan Rather stepped down from the CBS anchor chair last winter, producers have visibly tweaked the newscast, changing the way it is written and selecting different types of stories for the broadcast.

Couric, the network hopes, will step into the more-relaxed atmosphere of the Schieffer-led show without too jarring a change.