CBS comedy “The Big Bang Theory” was the No. 1 program on the first Thursday of the season, but the net’s new drama “Person of Interest” fared just OK in its bow. Fox’s “The X Factor” held up nicely in its second night and NBC’s “Whitney” looked pretty good, while it was a sluggish start for ABC’s “Charlie’s Angels” and a modest launch for NBC’s “Prime Suspect.”

Fox won the night in 18-49 – its first premiere-week Thursday victory ever – while CBS edged out Fox in adults 25-54 and prevailed easily in total viewers, according to preliminary Nielsen estimates.

Fox’s “The X Factor” averaged a solid 4.1/11 in 18-49 and 12.1 million viewers overall from 8 to 10 p.m., down just slightly from its Wednesday premiere and lifting the net to a victory in 18-49 and younger demos. Fox’s two-hour nightly average was the best for the net on the opening Thursday of the season in 15 years among adults 18-49 and 18 years among total viewers. “X Factor” placed second in 18-49 to “Big Bang” in the night’s opening hour and then won from 9 to 10 p.m., with its best numbers coming at 9:30 (4.7/11 in 18-49, 13.3 came at 9:30 when it averaged a 4.7/11 in the demo.

At CBS, “The Big Bang Theory” was in line with its Thursday premiere of a year ago, averaging a strong 4.8/15 in adults 18-49 and 14.1 million viewers overall and then faring a bit better with a second original episode at 8:30 p.m. (5.0/14 in 18-49, 14.6 million viewers overall). It was followed by new crime drama “Person of Interest” (3.1/8 in 18-49, 13.2 million viewers overall), which ran fourth in 18-49 (down a bit from last year’s “CSI”) while winning its hour in total viewers. “The Mentalist” closed things out (2.8/7 in 18-49, 13.4 million viewers overall), down from last year.

At NBC, the post-Steve Carell era began on “The Office” with a good showing (3.9/10 in 18-49, 7.6 million viewers overall), down about 10% from last year’s bow but a close second to “X Factor” for the half-hour’s lead in 18-49. And it was followed by the debut of “Whitney” (3.2/8 in 18-49, 6.7 million viewers overall), which held nearly 85% of its lead-in. A year ago, “Outsourced” opened with a 3.6 demo rating in the 9:30 p.m. half-hour, retaining 81% of its “Office” lead-in.

The Peacock then fell back at 10 p.m. with the premiere of Maria Bello drama “Prime Suspect” (1.8/5 in 18-49, 6.0 million viewers overall), though it was ahead of last year’s low-rated “The Apprentice” in the timeslot. And NBC wasn’t that hot in the night’s opening hour with “Community” (1.7/5 in 18-49, 4.0 million viewers overall) and “Parks and Recreation” (2.0/6 in 18-49, 4.1 million viewers overall) – down about 20% from last year’s combo of “Community” and “30 Rock.”

ABC’s “Charlie’s Angels” wasn’t a disaster in its bow (2.1/6 in 18-49, 8.7 million viewers overall), finishing a distant third in the 8 o’clock hour but an improvement over last year’s short-lived “My Generation.” From 9 to 11 p.m., a two-hour “Grey’s Anatomy” (4.1/10 in 18-49, 10.3 million viewers overall) was down more than 20% from last year’s hourlong opener, but won its second hour in demos, peaking at 10:30 with a 4.4 rating in 18-49.

CW saw its compatible drama duo of “The Vampire Diaries” (1.2/3 in 18-49, 2.5 million viewers overall) and “The Secret Circle” (0.9/2 in 18-49, 2.0 million viewers overall) take a hit opposite the Big Four premieres.

Preliminary 18-49 averages for the night: Fox, 4.1/11; CBS, 3.6/10; ABC, 3.4/9; NBC, 2.4/6; Univision, 1.6/4; CW, 1.0/3.

In total viewers: CBS, 13.6 million; Fox, 12.1 million; ABC, 9.8 million; NBC, 5.7 million; Univision, 3.6 million; CW, 2.3 million.