TV’s top two properties combined for one fantastic frame for Fox.

As the National Football League neared the end of its season with Sunday’s hugely watched semifinal playoff action, “American Idol” was just getting going with more big Nielsens for its audition round.

The two teamed to produce the highest-rated primetime week for any net (excluding Super Bowl and Olympics seshes) in 14 years, and Fox has now assumed the season lead in the adults 18-49 demo — rising three-tenths of a ratings point in one week.

Looking at last week’s Nielsen estimates, Fox’s 9.5 rating/24 share beat out the combined deliveries of the next five highest-rated nets: NBC (2.6/7), CBS (2.4/6), ABC (2.0/5), Univision (1.5/4) and USA (0.9/2). Net also cruised in all other categories, including total viewers (24.3 million).

In both 18-49 and total viewers, and excluding weeks when it aired the Super Bowl, the past week ranks as Fox’s top rated of all time.

For the season, according to Nielsen, Fox’s 3.6 rating in adults 18-49 puts it ahead of the other three major nets, which are all at a 3.3. Given the paucity of scripted originals on its rivals, that gap will open up even more.

In fact, if the writers strike doesn’t end in time for original episodes of shows such as “Grey’s Anatomy,” “Desperate Housewives” and “CSI” to return by May, it’s likely Fox will prevail for the season by a record margin. The record in the 20-year history of the Nielsen People Meters is the 34% advantage NBC held over runner-up Fox in the 1997-98 campaign (6.7 to 5.0).

Fox won last season by 11% (4.1 to 3.7 for CBS) and should more than double that advantage this year. It has the strike-proof “Idol” through May as well as the Super Bowl next week to pad its averages.

Leading the way for Fox last week was Sunday’s National Football Conference championship between the New York Giants and Green Bay Packers, which averaged a massive 53.94 million viewers (and a 20.6/46 in 18-49). Contest, won by the Giants, peaked with more than 65 million viewers in its final half-hour, when the contest moved into overtime.

It became the most-watched non-Super Bowl football game in 13 years (since 56.8 million watched the 1995 NFC championship between Dallas and San Francisco). And it joins a select group of non-Super Bowl telecasts of the past 10 years to top the 50 million mark: the “Seinfeld” finale on NBC in May 1998; the 1998 Academy Awards (when “Titanic” won) on ABC; the 2004 finale of “Friends” on NBC; and the finale of the original “Survivor” on CBS in August 2000.

It was a huge Sunday all around for the NFL, as the late-afternoon AFC title game in which the New England Patriots beat the San Diego Chargers averaged a big 44.8 million viewers, making it the No. 2 telecast since last year’s Super Bowl, ahead of the Academy Awards (40.17 million).

Combined, the two conference title games — semifinals that determined the Super Bowl participants — averaged 49.7 million viewers, up 10% over last year and the best in 13 years (since 49.9 million in 1995).

Elsewhere for Fox, “American Idol” returned with massive numbers, though it was down by more than 10% vs. a year ago (Daily Variety, Jan. 22).

Still, Tuesday’s two-hour premiere (13.8 rating/32 share in adults 18-49, 33.41 million viewers overall) towers above all other entertainment telecasts of the season. In comparison, it’s 55% higher than the top show in the demo (a 9.1 for ABC’s season premiere of “Grey’s Anatomy”) and 31% higher in total viewers (25.4 million for the season preem of “CSI” on CBS).

Wednesday’s “Idol” also crushed the competition (12.6/30 in 18-49, 30.44m), and that midweek mojo seemed to carry over to Thursday, where “Are You Smarter Than a 5th Grader” (3.7/10, 11.58m) and “Don’t Forget the Lyrics” (3.4/9, 8.79m) both hit season highs to help Fox win an in-season Thursday with regular programming for the first time in 15 years.

Earlier in the week, Monday’s time-period debut of “Terminator: The Sarah Connor Chronicles” (4.2/10 in 18-49, 10.08m) ran second in most categories and first in key male demos.

At NBC, Monday’s winning tandem of “American Gladiators” (4.6/11 in 18-49, 10.61m) and “Deal or No Deal” (5.0/12, 15.08m) remained potent, with the latter hitting season highs.

Other nonscripted fare also clicked, as “Biggest Loser” hung in opposite “Idol” on Tuesday (3.0/7 in 18-49, 7.18m), and “Celebrity Apprentice” emerged as the top program in demos on Thursday (4.0/10, 9.14m).

CBS had a quiet week, led by Monday’s original “CSI: Miami” (4.3/11, 14.80m). On Tuesday, “NCIS” (3.0/7 in 18-49, 15.82m) held up well against “Idol,” virtually hitting its season average in total viewers.

ABC struggled, even though it had a bunch of firstrun 10 o’clock dramas. Among them, “Cashmere Mafia” fared best (2.2/6 in 18-49, 5.46m), but it still ran third in the slot. Sunday highlight was a two-hour “Extreme Makeover: Home Edition” (3.8/8, 10.50m) that ran second to Fox’s football.

Univision saw good results Sunday for the premiere of its first primetime animated series, “El Chavo: La Serie Animada” (1.5/3 in 18-49, 3.35m). Opposite football on Fox, it stood as the No. 1 entertainment program on television for the 7 o’clock hour in adults 18-34 (1.8/5).

At CW, Tuesday’s “One Tree Hill” (1.3/3, 2.72m) didn’t crater vs. “Idol,” but Wednesday’s disappointing “Crowned” (0.6/2, 1.45m) was overwhelmed by the juggernaut. And the net put up more embarrassing numbers Sunday, where some of its shows did a 0 share — yep, the ole goose egg.

In cable, USA prevailed behind three of the four top shows of the week in demos: “WWE Raw” (1.9/5 in 18-49, 4.91m for its two hours) and the Friday tandem of “Monk” (1.5/4, 5.46m) and “Psych” (1.4/4, 4.21m). Only show on another network in the same league was Bravo’s hot “Project Runway” (1.9/5, 3.34m).

AMC was pleased with the Sunday bow of its new drama “Breaking Bad,” which drew 1.41 million viewers in its 10 o’clock slot despite opposing Fox’s huge football game. In a positive for the net, the show skewed younger and more male than its average fare, producing nice timeslot gains as well.

And a trio of nets had good news from original movies over the weekend, led by ABC Family’s “Bring It On: In It to Win It” (1.2/3 in 18-49, 4.55m). Cheerleading sequel pic stood as the No. 1 cable program in its time period Sunday.

Also, on Saturday, Hallmark Channel’s “The Good Witch,” starring Catherine Bell, averaged a solid 4.23 million viewers, the second biggest aud to date for the preem of an original telepic on the net. And Oxygen set a network record for an original movie Saturday with “Husband for Hire” (1.11 million).