NBC remains the surprise early ratings leader this season, notching a second straight victory among young adults last week on the strength of “The Voice,” “Revolution” and “Sunday Night Football.”

CBS, with top-rated scripted series “The Big Bang Theory” and the Sunday football overrun this week, pulled into a tie with NBC for the lead in adults 25-54 and won big as usual in total viewers.

The Peacock was again the only network up vs. last year while ABC, CBS and Fox posted double-digit declines.For the first time since 2003, NBC has won the first two weeks of the season outright in adults 18-49.

The best-looking rookie performers in the early going are NBC’s “Revolution” and CBS’ “Elementary.” And while no new comedy has performed as strongly, four of them — NBC’s “Go On” and “The New Normal” and Fox’s “Ben & Kate” and “The Mindy Project” — have garnered enough viewer interest to earn full-season renewals from their respective nets.

The shows in most immediate danger of exiting are Fox’s Monday drama “The Mob Doctor” and CBS’ Friday drama “Made in Jersey” and Monday comedy “Partners.”

With the lackluster overall numbers for the fall crop and some inevitable declines for veteran series, the Big Four are collectively lagging. But thanks to DVR playback, some of those declines have evaporated.

In final Live-plus-3 numbers for premiere week, the Big Four combined for an 11.75 rating in adults 18-49 — down 13.3% from last year (13.56) but better than the 16.1% decline they were showing in Live-plus-Same Day numbers reported last week (9.82 vs. 11.71). Similarly, the L3 year-to-year falloff in total viewers was 9.2% (38.08 million this year vs. 41.94 million last year) vs. 11.0% in the originally reported L+SD (33.30m vs. 37.41m).

These deficits could be lowered further if, as surmised, DVR playback is being pushed back later, in part due to increased DVR usage and more ratings points this fall for NFL action.

Nielsen is scheduled to release full-week DVR playback for premiere week next Monday.

Overall for the week of Oct. 1-7, Nielsen same-night viewing estimates show NBC winning rather easily in adults 18-49 with a 2.8 rating/8 share. It was followed by CBS (2.4/7), Fox (2.1/6), ABC (2.0/6) and Univision (1.4/4). In adults 25-54, NBC and Fox tied at 3.2/8.

CBS was the runaway leader in total viewers (10.4 million), drawing nearly 3 million more than either ABC or NBC.

In 18-49, NBC claimed the week’s No. 1 program, “Sunday Night Football” (7.2/18 in 18-49, 18.31 million viewers overall); the No. 1 unscripted series, “The Voice” (4.6/12, 12.55m); and the No. 1 new series, “Revolution” (3.2/8, 8.32m).

The net remains a non-factor on Thursday, though, where “30 Rock” kicked off its final season meekly (1.4/4, 3.46m).

At CBS, “The Big Bang Theory” (4.9/16, 15.18m) was the week’s top nonsports telecast in both 18-49 and 25-54 (6.2/17). And “NCIS” was the No. 2 drama in 18-49 (3.7/11), No. 1 drama in 25-54 (15.18m) and the week’s No. 1 program overall in total viewers (18.87 million).

Among new dramas, “Vegas” (2.0/6, 12.11m) and “Elementary” (2.5/7, 11.13m) fell off some in their second weeks, but the latter remains strong and is showing impressive DVR playback. Not so hot is Friday newbie “Made in Jersey” (0.8/3, 6.78m).

Fox’s “The X Factor” on Wednesday (3.5/11, 9.71m) and “Glee” on Thursday (2.6/7, 6.07m) showed week-to week gains, but new Monday drama “The Mob Doctor” is ailing (1.0/2, 3.46m). On the net’s Tuesday comedy block, anchor “New Girl” remains solid (2.8/7, 4.99m) while its other shows, including newbie “The Mindy Project” (1.9/5, 3.68m), aren’t doing much.

At ABC, “Grey’s Anatomy” remains a bright spot (3.8/10, 10.84m), while its Thursday lead-in “Last Resort” (1.9/6, 8.00m) was still in the OK range in its second week. Falling off a bit more week to week was Sunday newcomer “666 Park Avenue” (1.7/4, 4.99m), though its decline was in line with that of lead-in “Revenge” (2.6/6, 8.36m).

Net’s “Once Upon a Time” was Sunday’s No. 1 drama in demos (3.4/9 , 9.84m).

The first presidential debate drew a big 67.2 million viewers across 11 broadcast and cable networks Wednesday. This was well above the 52.4 million who tuned into the first Obama-McCain debate in 2008.

Of note on cable was Sunday’s Lifetime original movie “Steel Magnolias” (2.4/6 in 18-49, 6.51m), an all-black production based on the 1989 theatrical. It became the net’s most popular pic in six years, and “Steel” beat out both CBS and ABC in 18-49 from 9-11 p.m.