First the Cubs.

Now the Peacocks.

A season of miracles.

NBC, the Cubs of networks, is No. 1 in prime-time ratings so far this TV season. In addition, the Nielsen Television Index puts NBC in first place among every young-adult demographic group, including the women 18 to 49 that sponsors die for. The TV season is only in its fifth week, but for a network traditionally described as "perennially third rated" or in "dismal last place," this is revolutionary.

NBC has almost won the division championship, at least in terms of improving performance over recent years and raising internal morale. Now some at the network may even be thinking about the World Series -- giving perpetual front-runner CBS a serious challenge.

"Everybody is like an inch taller around here," says Brandon Tartikoff, the shockingly young (35) shaggy-haired Yalie who is president of NBC Entertainment and architect of a fall schedule that has seen NBC's prime-time averages rise 14 percent over last year's. CBS, by comparison, is down 6 percent and ABC down a drastic 15 percent. Even with the World Series -- the real one, which NBC carried this year -- factored out of the averages, NBC is up dramatically, and what amazes even NBC insiders is that not only have big-draw movies like "The Burning Bed" performed well, but NBC's new weekly shows, the backbone of any schedule, are gangbusters.

"We've been down so long, you don't want to jinx it by being premature," says NBC executive vice president M.S. Rukeyser Jr. from New York. "But it's demonstrably true that there's a lilt in steps around here that was not there before. It's certainly a helluva lot more fun coming to work each day. Because we screwed it up for so long, we became a terrific opportunity, one that now seems to have happened."

Tartikoff is in the mood to be self-effacing rather than to take bows. When commenting on the fact that this year's new schedule is doing markedly better than last year's, he says, "I designed both," and notes, "We set extremely low standards for ourselves last year to improve upon." But the fact is, Tartikoff may be working the kind of wonder at NBC that Fred Silverman, a Tartikoff mentor, worked at ABC years ago when that network went from the gutter to the throne room.

The difference is, Tartikoff hasn't done it only with gimmicky junk. The NBC prime-time schedule includes such honorabilities as "Hill Street Blues," "Cheers," "Family Ties," "Miami Vice," "St. Elsewhere," "Remington Steele" and the most successful new comedy of the year, "The Cosby Show," which has managed the seemingly impossible and beat its competition, CBS' "Magnum, P.I.," every week so far this season.

"Last year, almost nothing worked," says Tartikoff from Burbank. "Now, almost everything works." All nine new fall shows NBC introduced a year ago were canceled before the season was over. This season, Tartikoff's only major problems are "Partners in Crime" and "Hot Pursuit," two crime bombs on Saturday night that are almost sure to be canceled.

Even Tartikoff, who says he makes a lot of $10 bets around the office about how shows on all three networks will do in the ratings (he says he won $100 off the CBS miniseries "Mistral's Daughter"), didn't think "Cosby" would do as well as it has. "I thought that as the season progressed, we would nibble away at 'Magnum.' I thought it would do a share or two better than the best performance of 'Gimme a Break' last year, inching up toward a 29 share," Tartikoff says. Last week, "Cosby" was in seventh place with a 34 share. "Magnum" was in 11th place with a 32.

A rating point is a percentage of the total number of TV households. A share is a measure of sets in use during a particular time period. "Punky Brewster" and "Silver Spoons" are low-rated comedies that air opposite the CBS dynamo "60 Minutes" on Sunday nights, but both are getting enormously better shares than the program NBC had in the period last year, "First Camera," and so are considered virtual hits.

Of course, the NBC peacock has come leaping out of the starting gate before, only to stumble and fall on its face. In 1980, then-NBC chairman Silverman hyped his way to heaven with "Shogun," a well-received mini-series that led off the season. NBC staffers in Burbank were running around with T-shirts that had a steaming locomotive and the words "Silverman Express" plastered on the front. But once viewers got a look at the regular weekly lineup, they deserted NBC in proverbial droves. What's important to the current NBC winning streak is that, as Rukeyser says, "This is the best start in recent memory for the programming we're going to have on every week."

New York advertising executive Paul Schulman, who buys network time, told Advertising Age this week, "NBC is in super shape, CBS is in pretty good shape, and ABC has a lot of problems."

ABC's certified disasters include "Hawaiian Heat," "Matt Houston," "Jessie," and the already canceled "People Do the Craziest Things." ABC's "Hardcastle and McCormick" is losing ground to NBC's "Knight Rider" on Sunday nights, the most important night of the viewing week.

Why is NBC doing so well? Not every component of the success story is a triumph of NBC chairman Grant A. Tinker's much ballyhooed "quality" approach. One crucial key was the success in midseason last year of the lowly "Foul-Ups, Bleeps and Blunders" on Monday nights. "If we hadn't had that show last year, I don't know if you'd be having this conversation with me now," says Tartikoff. "It took us from third to first on Monday nights in that period and gave us a launching pad for other shows."

But among other reasons for the improved outlook, Tartikoff cites the fact that "the network is stronger, the shows are better. We've gone for shows that are a little bit more mainstream. We've got Bill Cosby and Michael Landon in our schedule. The concepts are very accessible to a viewer. You don't have to spend half an hour explaining what the show is about." Last year's NBC shows included a comedy about a talking orangutan and an adventure show about a man who could turn into a panther or a birdie. What he turned into was dust.

Tartikoff confesses he does have his worries this season. He can't just go home to his hot tub and gloat.

"I'm a little bit nervous about ABC's 'Paper Dolls,' " he says. "It's like the killer in 'Halloween.' You keep stabbing it in the head, and it keeps rising up above the couch. We and CBS are doing our best to make sure the thing doesn't become another 'Dynasty.' We've been doing our job, but I'm afraid the body's not cold yet."

On Friday, NBC will introduce what could be another relative smash: "V," the helter-skelter futurecamp spectacular that has already been sampled by viewers as two high-rated mini-series. At 8 p.m. Fridays, the CBS "Dukes of Hazzard" is already foundering, and an NBC smash in the lead-off position could undermine the CBS "Dallas"-"Falcon Crest" stranglehold on the evening.

" 'V' will be a major success for us even if it doesn't succeed," Tartikoff says in pure videospeak. "Even if it goes steadily downhill all season, if it starts at a high enough level to get some circulation for 'Hunter' and 'Miami Vice,' which follow it, then it will have succeeded. If it started with a 32 share and then went to a 30 and then to a 25, it would still be higher than what we had all last year in that time slot." Tartikoff predicts "V," which has a special effects budget of $75,000 per show, will average a 28 or 29 share. "Dukes" had a 22 share last week without first-run NBC competition.

For Tartikoff, the good fortune comes as something of a reprieve. A few of the NBC affiliates were grumbling loudly that if the network showed no major improvement this year, they would ask for Tartikoff's head. Says Rukeyser, "You can't blame people who have watched us be third for a long time for feeling there ought to be changes made, but the vast majority of our affiliates have enormous respect for Brandon, and you can't be around Brandon and not respect him."

He is the most respected and best liked of the network programmers, although some NBC executives, including Tinker, were reportedly irked last year by the way Tartikoff was soaking up ink in magazines and newspapers, and even guest-hosted a "Saturday Night Live," as if on a self-publicizing binge. And here was the network a miserable third. They told him to cool it. Now he has something concrete to brag about.

"It's a lot more fun not to have to constantly be doing 25 pilots to solve 15 problems," Tartikoff says. "It's important that we maintain that competitive edge, but it's also important -- and I think this is Grant's great contribution -- to maintain an environment that is conducive to producers. If we start turning into jerks because we've got a couple of successful shows, then that will violate what we've been trying to do."

Has success, so long elusive, changed him? "I don't think I've become any nicer," Brandon Tartikoff says. "But then, I don't think I was so bad in defeat."