An old-school NFL conference championship matchup played in sub-zero temperatures produced boffo ratings for Fox on Sunday night, likely drawing the largest non-Super Bowl football aud in 12 years.

The New York Giants’ 23-20 victory over the favored Green Bay Packers obliterated the competish, drawing four, five or more times the audience of firstrun shows opposite it, including “Extreme Makeover: Home Edition” on ABC and the “Amazing Race” finale on CBS.

The National Football Conference title game, which began at about 6:45 p.m. ET, averaged 48.6 million viewers on Fox’s affiliates from 7 to 10 p.m., according to Nielsen. It’s expected that the game should come in at or north of 50 million viewers when Nielsen finalizes its national ratings Wednesday.

That would make it the most-watched conference championship game since 1996, when the Packers-Dallas Cowboys NFC contest on Fox averaged 52.68 million viewers. Last year’s American Football Conference championship game between the Indianapolis Colts and New England Patriots (46.7 million) stood as the most-watched AFC title game in 21 years.

The 50 million figure is a level rarely achieved by a single-network telecast. In fact in the last 10 years, only Super Bowl games, the 1998 Academy Awards (the year “Titanic” was crowned), the 2000 finale of the original “Survivor” on CBS and series finales of NBC laffers “Seinfeld” and “Friends” have topped the number.

Sunday’s matchup wasn’t the pairing that had been anticipated most of the season — the Packers against the top-seeded Cowboys — but it did pit teams rich in tradition. Fox also benefited from a close game throughout as well as a brutal cold front that hit the Northeast and upper Midwest, likely keeping more potential viewers in front of their TV sets.

And Fox has to feel really good about the matchup it has for its fifth Super Bowl telecast, as the Giants take on the undefeated New England Patriots on Feb. 3.

While the teams hail from the same region, they both have strong national followings. The Patriots, in particular, have become a huge story this season with their run of perfection, taking an unprecedented 18-0 record into the big game.

Total-viewer estimates were not available Monday for the Patriots’ 21-12 victory over the San Diego Chargers in the AFC championship game Sunday on CBS (3-6 p.m. ET), but the game drew a very strong 27.4 household rating/48 share in Nielsen’s metered markets.

This puts it down only a bit from last year’s huge Indy-New England matchup (28.1/40), but it’s up vs. last year’s New Orleans-Chicago NFC matchup on Fox (26.2/45), which aired in the same late-afternoon window.