Fox has swooped in and won another Thursday in demos with a two-hour ”The X Factor,” while CBS comedy ”How to Be a Gentleman” struggled in its premiere and other scripted newbies like NBC’s ”Whitney” and CBS’ ”Person of Interest” posted OK but nothing-special numbers in their second outings.

According to preliminary national estimates from Nielsen, Fox’s ”The X Factor” averaged a potent 3.8 rating/10 share in adults 18-49 and 11.9 million viewers overall from 8 to 10 p.m., peaking with a 4.3 demo score and nearly 13 million total viewers and lifting Fox to victory in adults 18-49 and 25-54. When nationals come in this afternoon, ”X” is expected to be down in the single-digit percentages vs. last week , a better hold than most scripted series.

At CBS, ”The Big Bang Theory” dominated Thursday’s 8 o’clock half-hour (4.8/15 in 18-49, 14.5 million viewers overall), on par with its week-ago delivery in the half-hour and topping runner-up ”X Factor” by 6 shares in 18-49. It was a big dropoff, though, at 8:30 p.m. for the debut of ”How to Be a Gentleman” (2.7/8 in 18-49, 9.0 million viewers overall), which significantly underperformed the retention of last fall’s ”Bleep My Dad Says.” News was better for the Eye at 9 p.m., where ”Person of Interest” (2.7/7 in 18-49, 12.4 million viewers overall) declined a decent 13% in the demo and 7% in total viewers despite a lead-in that was less than half of what it was on premiere night; though it again finished fourth in 18-49, it moved up to third in 25-54 (3.8/9). And at 10, ”The Mentalist” (2.5/7 in 18-49, 12.7 million viewers overall) placed second in 18-49 and first in 25-54 and total viewers.

NBC again started slowly with ”Community” (1.8/5 in 18-49, 4.0 million viewers overall) and ”Parks and Recreation” (2.1/6 in 18-49, 4.4 million viewers overall) before rising at 9 p.m. with ”The Office” (3.4/9 in 18-49, 6.6 million viewers overall). At 9:30 p.m., ”Whitney” (2.5/6 in 18-49, 5.4 million viewers overall) fell off a little more than its ”Office” lead-in, but its 74% retention is still fairly good. Dropping into the dangerously low range, though, was 10 p.m. drama ”Prime Suspect” (1.5/4 in 18-49, 5.6 million viewers overall) , though it was still a bit ahead of last season’s weak ”The Apprentice.”

ABC saw ”Charlie’s Angels” (1.5/4 in 18-49, 7.2 million viewers overall) tumble more than 25% from its OK premiere of last week, dropping to last among the Big Four in demos for the 8 o’clock hour. ”Grey’s Anatomy” followed (3.5/9 in 18-49, 10.0 million viewers overall) with a second-place demo finish , down 15% from its two-hour premiere of last week and more than 20% from its second week of last year but still the night’s No. 1 drama in demos. And at 10, ”Private Practice” (2.8/8 in 18-49, 7.9 million viewers overall) had a solid season premiere, leading its broadcast competition among young adults with its top score since December.

CW’s ”The Vampire Diaries” (1.3/4 in 18-49, 2.7 million viewers overall) was up across the board vs. last week (including by 17% in adults 18-34), while ”The Secret Circle” (0.9/2 in 18-49, 2.1 million viewers overall) was flat or up a bit in most categories.

Preliminary 18-49 averages for the night: Fox, 3.8/10; CBS, 3.0/8; ABC, 2.6/7; NBC, 2.1/6; CW, 1.1/3.

In total viewers: CBS, 12.3 million; Fox, 11.9 million; ABC, 8.4 million; NBC, 5.2 million; CW, 2.4 million.