The New York Giants’ overtime victory over the San Francisco 49ers in football’s NFC Championship game scored monster ratings for Fox on Sunday — drawing more than four times the combined young-adult viewership of ABC, CBS and NBC. ABC’s ”Once Upon a Time” was the top-rated series, down just a tick from last week.

Reliable preliminary Nielsen estimates for the NFC Championship won’t be available until later today, but Fox’s stations averaged an 18.7 rating/40 share in adults 18-49 and 50.1 million viewers overall for the full duration of primetime Sunday. These numbers are expected to grow nicely in the nationals as they don’t accurately reflect West Coast viewing, and the game started at around 6:40 p.m. ET. The net than followed at 10:57 p.m. ET with a special ”American Idol,” which drew a 7.9 demo rating and 19.8 million viewers, according to time zone-adjusted preliminary Nielsen numbers ordered by Fox; the net had hoped to get ”Idol,” on the air earlier, but the late football finish meant that the music series ended up airing out of primetime in much of the country for all but its first few minutes.

Earlier in the day on CBS, the network’s coverage of the AFC Championship between the New England Patriots and Baltimore Ravens drew a 29.1 household rating/51 share in Nielsen’s metered-market overnights — the best score for an afternoon AFC title game in 18 years; game peaked with a 34.9/56 in its final 15 minutes. In primetime, the net aired ”60 Minutes” (1.5/3 in 18-49, 7.9 million viewers overall), followed by ”Undercover Boss” (2.2/5 in 18-49, 9.2 million viewers overall) and repeats of ”The Good Wife” (1.1/2 in 18-49, 5.6 million viewers overall) and ”CSI: Miami” (1.4/3 in 18-49, 6.2 million viewers overall). ”Boss” was down sharply from last week when it didn’t face football.

ABC stuck with its regular lineup, opening with ”America’s Funniest Home Videos” (1.2/3 in 18-49, 5.2 million viewers overall) and then surging at 8 p.m. with ”Once Upon a Time” (3.2/7 in 18-49, 9.3 million viewers overall), which while below average, was just slightly off from last week when it faced only the concluding 10 minutes of football. Also within a tick was ”Desperate Housewives” (2.6/5 in 18-49, 7.5 million viewers overall), and ”Pan Am” closed out the night (1.3/3 in 18-49, 3.9 million viewers overall) up slightly from last week.

NBC aired a two-hour ”Dateline” (1.1/2 in 18-49, 5.2 million viewers overall) followed by two special original episodes of the canceled cop drama ”Prime Suspect” (0.8/2 in 18-49, 4.3 million viewers overall at 9 and 0.7/2 in 18-49, 3.6 million viewers overall at 10).

Preliminary 18-49 averages for the night: Fox, 18.7/40; ABC, 2.0/4; CBS, 1.6/3; NBC, 0.9/2; Univision, 0.8/2.

In total viewers: Fox, 50.1 million; CBS, 7.2 million; ABC, 6.4 million; NBC, 4.6 million; Univision, 2.5 million.