NBC had a difficult time in the ratings Tuesday night, based on Nielsen overnights, with two of its series slipping to season lows in the key 18-49 demo, TVbytheNumbers.com reports.

Both “Go On” and “The New Normal” hit new lows — eroding just a bit more after both shows sank to season lows last week. “Go On’s” 1.2 average rating in 18-49 and “New Normal’s” 1.1 were both down one-tenth of a ratings point from a week ago.

Elsewhere on NBC, two installments of “Betty White’s Off Their Rockers” were also down. The show’s 1.4 rating at 8 p.m. was down two-tenths, and a 1.5 at 8:30 represented a fall-off of three-tenths. “Dateline” rounded out the network’s rough evening at 10 p.m. with a 1.3.

CBS’s lineup of original dramas easily carried the night: “NCIS” dipped two-tenths from its previous original episode to a 3.7 to earn the title of top-rated show of the night; “NCIS: Los Angeles” rose four-tenths to a 3.1; and “Vegas” ticked up three-tenths to a 1.9 to win the 10 p.m. hour.

Fox put up a little bit of a fight, with “New Girl” leading the way with a 2.5 in viewers 18-49, up three-tenths from last week. Two episodes of “Raising Hope” delivered a 1.7 and a 1.5 in viewers 18-49, while “The Mindy Project” also came through with a 1.7, up two-tenths.

ABC was well out of the running, with “The Taste” down a half-point from last week’s premiere, settling for a 1.6 in the 18-49 demo. Two episodes of “Happy Endings” managed only a 1.2 and a 1.3, and ABC aired a “Jimmy Kimmel Live” rerun at 10 p.m. (1.2 average rating).

When the dust settled, CBS was comfortably ahead for prime time overall with a 2.9 average rating in 18-49, followed by Fox (1.8 average), Univision (1.8), ABC (1.3) and NBC (1.3). CBS had a huge lead in total viewers with 16.7 million, trailed by NBC with 4.6 million, Univision with 4.2 million, Fox with 3.8 million and ABC with 3.6 million.