"Once Upon a Time" (Kharen Hill/ABC)

An average of 13 million people caught the unveiling of ABC’s new fairytale fantasy, “Once Upon a Time” Sunday, even though it aired in the teeth of World Series Game 4 on Fox, and that wacky Sunday football game in which the New Orleans Saints defeated the winless Indianapolis Colts, 62-7 to become the most lopsided game in the six-year history of NBC’s “Sunday Night Football.”

“Once” now has the fifth biggest audience of any new series roll-out this new TV season.

Which, of course means it did better than shows TV-industry navel lint pickers predicted would be the Next Big Thing: Simon Cowell’s Fox singing competition “X Factor” opened with 12.5 million on a Wednesday in September and clocked 12.5 million the next night too.

Meanwhile, Fox’s $20 million two-hour time-traveling dino-drama “Terra Nova” attracted an average of 9.2 million viewers on the day it launched.

In case you missed it, “Once” is about a 28-year-old bail bonds collector chick, who was abandoned as a baby and who gave her own baby boy up for adoption years earlier. Only, her now 10-year-old son, Henry tracks her down because he thinks Mom is Snow White and Prince Charming’s missing daughter who was sent away to protect her from the Evil Queen’s curse – which somehow trapped the fairytale world forever, frozen in time and now accessible only from some picturesque New England town called Storybrooke.

Would it surprise you to learn women drove “Once” ratings? Didn’t think so. How about women between the ages of 25 and 54 years? We’re sure there’s an “Oprah’s Lifeclass” episode somewhere in there.

Anyway, “Once Upon a Time” becomes the fifth most successful new-series launch of what’s shaping up to be a zippy 2011-12 TV season.

Among viewers of all ages and backgrounds, “Once” is ranked No. 5, behind:

— CBS’s “2 Broke Girls” (which enjoyed a 30-million-viewer “Two and a Half Men” lead-in audience)

— CBS’s Poppy-Montgomery-can’t-forget-a-detail cop drama ‘Unforgettable” (which has the “NCIS” ratings behemoth as its leadin)

— CBS’s new JJ Abrams drama series “Person of Interest”

— ABC’s retro Tim Allen sitcom “Last Man Standing.”

Among 18-49 year old viewers – a.k.a. advertiser catnip – “Once Upon a Time” also is ranked No. 5 for the season to date, behind:

— “2 Broke Girls”

— Fox’s new Zooey Deschanel comedy “New Girl”

— “X Factor” Wednesday

— “X Factor” Thursday.

Notice how that makes “Once Upon a Time” the season’s No. 1-ranked drama-series debut in the key demographic group? ABC noticed too.