“Pretty Woman,” ABC’s highest-rated theatrical film in 3 1/2 years, has escorted the alphabet network to an eyebrow-raising prime time Nielsens victory for the Oct. 26-Nov. 1 week.The combination of “Pretty Woman’s” attractive figures and political ads that pre-empted some of ABC’s lower-rated slots gave the network a second victory in the six weeks of the season so far. CBS has won the other four. It’s also the first time in four weeks the Nielsens haven’t been significantly skewed by baseball disruptions, and thus the week’s results are an important measureof the progress each web has made with its new fall lineups. And those results suggest a much closer race than CBS’ dominance of the season’s first weeks had indicated. That’s largely due to the significant fade of CBS’ previously impressive Friday lineup, as NBC shifted gears last week and threw an older-appeal “Perry Mason” vidpic up against CBS’ older-audience sitcoms. That led to season lows for all five of the CBS Friday regulars. And the CBS position looks dramatically weaker when measured according to the important adults 18-49 demographic, a fairly broad measure of a net’s strength with the audiences most important to advertisers. Last week’s results by that measure were: ABC, an 8.4 rating, 22 share; NBC, 7.8/20; CBS, 6.0/15; and Fox Broadcasting Co., 5.1/13. ABC also has jumped out to an early lead in the tightly grouped November sweeps. For the first five nights of the Nielsen survey, the averages are ABC, 12.6/21; NBC, 12.5/21; CBS, 12.4/20; and Fox, 7.6/12. In nights corresponding with the Arbitron period, which begins a day earlier, averages show ABC and NBC with a 12.5/20 each, CBS with a 12.2/20, and Fox with a 7.8/12. But the good news for CBS is that last week it weathered both ABC’s best Sunday rating since the Jan. 27, 1991, Super Bowl and NBC’s second-best non-Olympics Sunday rating since April 2, 1989, and still finished just 0.7 points out of the household-ratings lead. NBC can be pleased with its strong second place among adults 18-49 (the biggest NBC advantage over CBS in that demo in a week without major sports disruptions since last December) and its overall 3% increase in that demographic vs. year-ago averages. On Monday of the current week ABC won again, thanks largely to the pre-emption of its weak 8-9 p.m. hour for political spex. Thus the Minnesota-Chicago “Monday Night Football” matchup (16.1/27) carried the night. Politically pumped up ABC pre-empted two hours due to political time buys last week, vs. an hour on NBC and a half-hour on CBS. Ross Perot ended his campaign with two half-hour spex (7.9/13 on ABC and 9.5/ 14 on CBS) and an hourlong ad (7.9/13 on NBC), while Bill Clinton ran a half-hour ad on each net (bagging a 6.7/11 on ABC, a 7.8/11 on CBS and a 10.8/16 on NBC). Ratings for these political spex are not figured into the webs’ weekly averages. With those ads disrupting the night, “Murphy Brown” (14.6/21) sagged to its lowest firstrun regular-slot rating since April 29, 1991. ABC grabbed its Oct. 26-Nov. 1 weeklong victory with “Pretty Woman” on Sunday , a night of extremely competitive programming that confirmed that the November sweeps are indeed on. “Pretty Woman” was ABC’s top single-episode film (theatrical or made-for-TV) since that net aired “Everybody’s Baby: The Rescue of Jessica McClure” May 21, 1989, and its best theatrical since “Romancing the Stone” April 9, 1989. NBC responded with “Saturday Night Live’s Presidential Bash,” the Peacock’s best non-Olympics performer in that slot since “Kindergarten Cop” aired there Feb. 9. It was also NBC’s highest-rated entertainment spec since the “SNL” 15 th-anniversary special Sept. 24, 1989. That left nightlong winner CBS in third from 9-11 p.m. despite its best regular-programming Sunday rating of the season. It also pushed Fox back in fourth place, dropping the Fox Sunday anchor “Married … With Children” to its lowest firstrun rating since May 14, 1989. Earlier in the evening, the return of cast member Damon Wayans boosted Fox’s “In Living Color” to its highest rating since March 29. On Saturday, with NBC planning to shake up its 8-9 p.m. lineup, “Here and Now” and “Out All Night” suddenly bolted into the timeslot lead for the first time. That better-late-than-never surge led NBC to an easy nightlong win, as Fox finished the night’s 8-10 p.m. block in second. Friday saw a major shift, as NBC relented in its pursuit of the younger audience and knocked older-skewing CBS deep into third. That left the young audience mostly to ABC, which easily won the night and led among adults 18-49 by 10 shares. NBC’s “Perry Mason” vidpic led three of its four half-hours in households (winning NBC’s best share for that slot since the Summer Olympics) but finished third for its two hours among adults 18-49. Still, the “Mason” 18-49 score topped averages for NBC’s previous series programming by 27%. CBS’ lineup was overruled by “Mason.” For example, “Designing Women” and “Bob ,” both undefeated this season prior to facing “Mason,” plunged to third in their slots last Friday, while Fox’s “America’s Most Wanted” captured its highest rating since last March 27. Thursday’s regular lineups finally all got out on the playing field, and the result was an NBC households win that was magnified in the adults 18-49 demo. “Wings” was especially impressive, losing just 1 share from its “Cheers” lead-in , equaling “Wings’ ” best-ever performance by that standard. But Fox showed frighteningstrength in the 8-9 p.m. hour. Special Halloween episodes scared up the weblet’s best-yet “Martin” rating, plus the strongest “Simpsons” rating since last March 26 (Daily Variety, Nov. 2). “Simpsons” enjoyed a 57 share with kids and a 47 among teens. “Martin” snared a 45 among teens. For “The Simpsons,” it was the show’s biggest timeslot margin of victory since June 17, 1990, back during its days on the Fox Sunday schedule. ABC is in trouble in the 8-9 p.m. hour. Last week the older-skewing “Delta” deposited its lowest household share yet, and then “Room for Two” followed with its steepest ratings fall-off from “Delta” this season. Thursday’s 10-11 p.m. race continues to tighten, meanwhile, as CBS just squeezed into second place that hour with the season premiere of “Knots Landing” (down 5% in rating from its ’91 premiere). NBC squeaks by Wednesday saw a close three-way race in households, won narrowly by NBC. ABC was a clear winner in adults 18-49, however, while CBS–despite the premiere of “In the Heat of the Night”–fell out of that race entirely. CBS debuted “Heat” and got its best regular-series share in its hour since “Raven” premiered June 24, but the skew is dramatically older, generating 37 and 33 shares among, respectively, women and men 50 and older. Getting squeezed into third for that hour (second in adults 18-49) is NBC’s “Seinfeld” and “Mad About You.” Tuesday was filled with all regular programming for the first time this fall, resulting in the strongest ABC Tuesday triumph of the season. “Roseanne” continues to blast into the stratosphere–last week the hit sitcom rocketed to its biggest timeslot margin of victory since Oct. 10, 1990. NBC fell out of the 8-10 p.m. race with “Quantum Leap” and “Reasonable Doubts ,” the latter dropping to the Peacock’s worst regular-season share that hour since the night of the Bay Area earthquake, Oct. 17, 1989. Still, “Dateline NBC” salvaged a 10-11 p.m. households win, its first since June 2, against ABC’s fading “Going to Extremes” (which still managed a narrow adults 18-49 victory). Monday went to ABC’s Buffalo Bills-N.Y. Jets “Monday Night Football” telecast (Daily Variety, Oct. 28). NBC got the best regular-slot rating ever for “Blossom.” Each rating point represents an estimated 931,000 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 watching TV during the timeslot involved.