On a night of midseason premieres and season finales on broadcast prime, CBS rolled to a comfortable win Thursday night even as its new comedy series "Bad Teacher" got off to a less-than-spectacular start, based on Nielsen overnights for the key 18-49 demo.

Leading out from "Two and a Half Men," the "Bad Teacher" premiere dropped four-tenths of a point from its lead-in to register a 2.1 average in viewers 18-49 in the 9:30 p.m. slot. That's the second-worst-ever number for CBS for an in-season comedy series premiere, trailing only "We Are Men" (2.0), TVbytheNumbers.com reports.

CBS had the top show on broadcast prime by a wide margin in "The Big Bang Theory," even with the series losing four-tenths from its previous original to notch a season-low 4.3 average in 18-49. "The Millers" held steady with a 2.5, while "Two and a Half Men" also delivered a 2.5, ticking up one-tenth. "Elementary" equaled its previous original's 1.6.

Among those chasing CBS, Fox had the edge with "Hell's Kitchen" equaling last week's 1.7 average in the 18-49 demo, "American Idol" slipping one-tenth to a 1.8, and "Surviving Jack" matching the series low it set a week ago, a 1.0.

ABC's premiere of "Black Box" in the 10 p.m. hour managed only a 1.5 average in adults 18-49.

ABC opened prime time with a "Jimmy Kimmel Live" repeat (0.6 average in 18-49), leading into "Grey's Anatomy," which tied its all-time low with a 2.3 average, falling three-tenths from a week ago.

NBC saw its one-hour season finale of "Parks and Recreation" settle for a 1.0 average in the 18-49 demo, rising one-tenth from the show's series low a week earlier. The network's two-hour prime-time "Saturday Night Live" special also managed only a 1.0.

For prime time overall, CBS outpaced its broadcast rivals with a 2.4 average in viewers 18-49, followed by Fox (1.5 average), ABC (1.4), Univision (1.2) and NBC (1.0). CBS also had a huge lead in total viewers, averaging 9.9 million to lead ABC (5.7 million), Fox (5.3 million), Univision (2.9 million) and NBC (2.5 million).