CBS is off and running this season, sweeping premiere week in all key categories for the first time in six years.

While other nets were forced to ponder timeslot switcheroos after poor premieres, the Eye — already home to more top 20 shows than any other network — successfully launched five programs. It’s up to viewers to decide if they like what they see, but thanks in part to some effective timeslot switches, the net has positioned its rookie class to succeed.

Overall during premiere week, though football on NBC and ESPN claimed the week’s top two spots in the 18-49 primetime program rankings, CBS dominated the rest of the top 25. The Eye accounted for 11 programs on the list (including three newbies), more than double the number for ABC (5), Fox (4) or NBC (4).

CBS also had four of the 11 returning programs on the Big Four to improve in 18-49 rating vs. the opening week of last year (“Two and a Half Men,” “The Big Bang Theory,” “Survivor” and “The Amazing Race”). That list also included three shows on both ABC (“Dancing With the Stars,” “Castle” and “Modern Family”) and NBC (“Law and Order: SVU,” “The Office” and “Dateline”) and “Glee” on Fox.

While there were no break-out hits among the 16 series bowing in premiere week, last season’s hottest newcomers — the 20th Century Fox duo of “Glee” (Fox) and “Modern Family” (ABC) — returned to record numbers, and have already moved into the upper echelon of program rankings.

Among adults 18-49, “Glee,” which ranked as the No. 13-rated scripted hour in premiere week a year ago — and finished at No. 5 for the season — started its sophomore sesh as TV’s top-rated hour. Similarly, “Modern Family” was merely the No. 7-rated half-hour in premiere week 2009 but broke out as the No. 1 half-hour last week.

Looking at Nielsen’s “live plus same-day” estimates for the Sept. 20-26 frame, CBS led comfortably in adults 18-49 with a 3.3 rating/10 share, followed by ABC and NBC (both at 2.8/8), Fox (2.6/7), Univision (1.6/5) and CW (1.1/3). CBS, NBC, CW and Univision were all up a tick vs. last year, while ABC declined 15% from its winning score of a year ago and Fox dropped 16%.

CBS also won with ease in both adults 25-54 (4.3/11 rating to 3.4/9 for runner-up ABC) and total viewers (12.5 million to 9.6 million for ABC).

The Eye remains a model of balance, with its 11 top-25 programs in adults 18-49 spread out over five nights; and on the genre side, it had five comedies, three dramas and three reality shows.

Among newbies, CBS could claim the top 18-49 show in Thursday’s “Bleep My Dad Says” (4.0/12 in 18-49, 12.58m), which finished just ahead of the Monday preems of “Hawaii Five-0” (3.9/11, 14.20m) and “Mike and Molly” (3.9/10, 12.23m); “Hawaii” was the top frosh bow in adults 25-54 (5.3/13).

A big story for CBS in premiere week was the move of “The Big Bang Theory” to Thursday and “Survivor” to Wednesday.

“Big Bang” and the show it aired behind on Monday, “Two and a Half Men” (4.9/12, 14.63m), tied as the net’s top shows in 18-49, while “Men’s” new lead-out “Mike and Molly” had a good bow (3.9/10, 12.23m). CBS also saw a solid bow for comedic legal drama “The Defenders” on Wednesday (2.9/8, 12.17m) and family cop drama “Blue Bloods” on Friday (2.2/7, 13.01m), which was that night’s top show and meshed well with transplanted vet “CSI: NY” (2.0/7, 10.35m).

On Sunday, CBS took advantage of an NFL overrun to funnel young viewers into its reality combo of “Amazing Race” (3.8/9, 11.54m) and “Undercover Boss” (3.8/10, 11.54m).

ABC, whose declines can mostly be attributed to less “Dancing With the Stars” and “Grey’s Anatomy” and a weaker Saturday college football game, was led by “Grey’s Anatomy” (5.4/14, 14.32m), and “Dancing With the Stars” (5.1/3, 21.29m), with the latter tying for fifth in 18-49 and standing as the week’s most-watched show overall.

Its star of the week, though, was “Modern Family” (5.1/14, 12.67m), which propped up a Wednesday lineup that saw a pretty good return for “The Middle” in its new 8 p.m. slot (2.7/9, 8.80m) and an OK bow for 8:30 rookie “Better With You” (2.5/7, 7.86m).

Net has a couple of shows — Wednesday drama “The Whole Truth” (1.5/4, 4.85m) and Thursday drama “My Generation” ) 1.6/5, 5.17m) — that must improve or they won’t last long.

Ditto for NBC, where the new “Outlaw” on Friday (1.1/4, 4.89m) and “The Apprentice” on Thursday (1.4/4, 3.84m) could get an early ax.

NBC had a respectable opening week, though, as “The Event” (3.6/9, 10.88m) showed nice time-slot gains in its Monday bow. New laffer “Outsourced” looked good (3.6/10, 7.49m) as part of the net’s Thursday comedy block behind “The Office” (4.4/12, 8.48m), and “Law and Order: SVU” was on the rise Wednesday (3.2/9, 10.08m). And on a weeknight basis, NBC improved vs. last year both in the 8-10 o’clock block as well as the 10 p.m. hour (where it had “The Jay Leno Show”).

And of course, “Sunday Night Football” (7.3/19, 18.15m) continues to perform better than last year, standing as the No. 1 program in 18-49 and other demos.

Fox had a sluggish premiere week, with most of its declines attributable to Monday, where “House” (4.2/11, 10.69m) and “Lone Star” (2.7/7.34m) settled for less than half of what the net did with a two-hour “House” last year. It also has a Friday problem with “The Good Guys” (0.9/3, 2.80m).

Fortunately, “Glee” roared back (5.6/16, 12.45m), and vets like “Bones” (2.7/8, 9.89m) and “Family Guy” (4.5/11, 9.13m) remain solid despite declines.

CW showed year-to-year gains as its shows, including rookies “Hellcats” (1.0/3, 2.31m) and “Nikita” (1.1/3, 3.15m), held up well.

The Friday reteaming of former Thursday skedmates “Smallville” (1.3/5 in 18-49, 2.98m) and “Supernatural” (1.3/4, 2.89m) seemed to help both shows, which combined to make CW the top English-language net on Friday in adults 18-34 (1.3/5). In cable, MTV’s “Jersey Shore” (3.1/9 in 18-49, 5.95m) held up very well opposite broadcast premieres, dominating its Thursday 10 p.m. hour in persons 12-34 (5.0/15).

HBO’s “Boardwalk Empire” drew 3.3 million viewers for its premiere telecast on Sunday, down from the 4.8 million who tuned in one week earlier.