A typically powerful CBS weekend carried the Eye network into first place in the April 4-10 primetime Nielsens race, snapping ABC’s four-week winning streak.The CBS victory, in the second-to-last week of the regular season, virtually assures the web of ending the year with its highest rating since the 1986-87 season. And while CBS has dominated the season, due in large part to the Winter Olympics, all three webs have a shot at reporting ratings increases compared to last season, something that hasn’t happened since at least the mid-’50s. The season three-net rating will probably be up by 2%-3%, which would be the biggest annual increase in 17 years, since 1976-77. CBS was in danger of losing its fifth-straight week last week before a sweep of Saturday and Sunday erased a 1.5-rating-point lead ABC had built up through Friday. ABC blew the week with its lowest-rated Saturday since the Winter Olympics and lowest-rated Sunday since the Super Bowl. Still, CBS’ most exciting ratings news came earlier in the week, as the Arkansas-Duke NCAA basketball championship grabbed CBS’ highest non-Olympics Monday rating in a year, and “Christy” earned CBS’ best non-Olympics Thursday 8- 9 p.m. grades in four months. CBS was also a close second for the week in adults 18-49, a valuable demographic that the other webs target more aggressively than does CBS. Last week’s averages in that demo were: ABC, a 6.8 rating, 19 share; CBS, 6.5 /18; NBC, 5.8/16 and Fox Broadcasting, 4.9/14. NBC has now finished third in its target demo the last three weeks in a row. Monday CBS has started off the current week with a win on the season’s final Monday. That gives the Eye 18 Monday firsts in the season’s 30 weeks, including 12 of 14 since the “Monday Night Football” season wrapped. The star of the night was “Hearts Afire” (16.0/25), which used a Rush Limbaugh guest appearance to top “Murphy Brown’s” lead-in rating (15.2/23) by 5 %. That’s CBS’ best post”Murphy” retention since a second “Murphy” aired in the 30-10 p.m. slot in September ’92. CBS’ “704 Hauser” (11.9/19) moved into the 8:30-9 p.m. half-hour with a rating that was down 3% from its “Evening Shade” lead-in (12.3/21). That’s the weakest a sitcom has done in the post-”Shade” slot since last July. NBC gave “704″ a rough reception by programming an extra “Fresh Prince” (13.6 /22) against it, helping NBC to its highest Monday rating since January. Sunday CBS swept the night’s half-hours, after its streak of Sunday sweeps (covering 70 half-hours and extending back to the Super Bowl) had been snapped the previous week. The Kirstie Alley-Sam Waterston vidpic “David’s Mother” dominated the 9 p.m. movie race in both homes and adults 18-49. “Ancient Prophecies” has brought NBC lots of good fortune. Less than six weeks after the show’s first run earned the Peacock’s best Tuesday 8-10 p.m. rating since the ’92 Summer Olympics, the rerun grabbed the top NBC Sunday 7-9 p.m. rating since the NBA All-Star game Feb. 13. Saturday CBS was never challenged, as the “Spoils of War” vidpic hit ABC’s worst Saturday 8-10 p.m. rating since November. It was also ABC’s lowest-rated Saturday pic since “Plymouth” crashed to a 4.3/10 in May 1992. Fox managed to lead among adults 18-49 during its 8-10 p.m. block. Friday “Sister, Sister” continues to help ABC control the night. In its second try in the 9:30 p.m. slot, “Sister” improved a bit on its premiere performance, which was ABC’s best in the slot, relative to lead-in, since last Christmas Eve. NBC’s Friday troubles were aggravated by the “Lives In Hazard” public-affairs special, which got roughed up for the Peacock’s weakest Friday 8-9 p.m. rating since Dec. 24. Thursday NBC won routinely, but CBS’ “Christy” topped the web’s regular-programming season average in the slot by 24% and ran second for the hour in both homes and adults 18-49. Against “Christy,” ABC’s “Byrds of Paradise” landed in the slot cellar for the first time. At 10 p.m., CBS’ “Traps” faded by 5% from its uninspiring premiere numbers of the previous week. NBC’s “Frasier” phoned in its highest rerun rating ever, leading into an adults 18-49 slot win for “Dateline NBC.” Wednesday Extra “Home Improvements” are keeping ABC far ahead on the night, while “These Friends of Mine” is helping out as well. Last week “Friends” held 82% of its “Improvement” lead-in, which is what slot regular “Grace Under Fire” averages. “Thunder Alley” is also getting meaty numbers in the middle of ABC’s “Improvement” sandwich, last week holding 97% of its lead-in. “Turning Point,” however, is pointed in the wrong direction, last week veering for the first time into last in the slot behind CBS’ “48 Hours.” That was despite a two-to-one lead-in advantage for the ABC newsmagazine. “Law and Order” was second that hour with its best rerun rating since January ’92. Fox’s “Beverly Hills, 90210″ and “Melrose Place,” meanwhile, were the week’s highest-rated dramas among adults 18-49. Tuesday ABC breezed, thanks in part tothe first rerun slot win for “NYPD Blue.” Fox’s premiere of “South Central” posted the second-highest Fox rating in the Tuesday 8-8:30 slot in 11 weeks. “South” was, however, also down by 15% from the share slot predecessor “Monty” earned with its Jan. 11 premiere. NBC continues to struggle on the night, with “The Good Life” falling to what may be that net’slowest firstrun regular-season rating ever for the Tuesday 8-8: 30 half-hour. Monday Arkansas-Duke basketball equaled the seventh-highest hoops rating in U.S. TV history (Daily Variety, April 6). CBS estimates 51.4 million viewers watched at least some of the game, virtually equaling the previous year’s championship as the “most-watched” U.S. basketball telecast ever as measured by the number of individual viewers (as opposed to the percentage of TV households, which is what the rating indicates). Each rating point represents an estimated 942,000 households, or 1% of U.S. TV homes. The share is the same sort of percentage, but is measured against only the households in which TV is being watched during the timeslot involved.