NBC saw mixed results for the premiere of “The Black Donnellys” last night. On the one hand, the show bettered last week’s rating for former timeslot occupant “Studio 60 on the Sunset Strip” by 35 percent. On the other, “Donnellys” showed an alarming dip in its second half and was nowhere near the rating “Studio 60” drew in its premiere last September.

“Donnellys” averaged a 3.5 adults 18-49 rating last night at 10 p.m., according to Nielsen overnights, up 35 percent over last week’s series-low 2.6 for “Studio 60.”

But that debut rating was partially inflated by runover from “Donnellys’” lead-in, “Heroes,” which ran to 10:03 p.m. last night. In its second half hour, the Irish mob drama dipped from a 4.1 to a 2.8, a decline of 32 percent.

Also, “Donnellys” was nowhere near the 5.0 that “Studio 60” averaged in its September debut, despite having a stronger lead-in. (“Heroes” debuted a week later.)

The big question now is how “Donnellys” will perform in its second week. It never bodes well for a show to see a big decline in its second half hour, no matter how strong its lead-in. But if “Donnellys” can continue to outrate “Studio 60,” NBC may be satisfied with that, at least for a bit.

The network did manage to win the night, something that “Studio 60’s” low numbers had been preventing the past few weeks.

NBC averaged a 4.9 average rating and a 12 share in 18-49s on a close night. CBS was second at 4.7/12, Fox third at 4.4/11, ABC fourth at 3.8/10, Univision fifth at 1.6/4 and CW sixth at 1.1/3.
 
As usual, NBC led the first two hours of the night, starting with a 4.9 rating at 8 p.m. for “Deal or No Deal.”  ABC and Fox tied for second that hour at 3.9, ABC for “Wife Swap,” in a season high, and Fox for “Prison Break,” with CBS fourth with a 3.6 average for “How I Met Your Mother” (3.6) and “The Class” (3.5). Univision was fifth with a 2.2 for “La Fea Mas Bella” and CW sixth with a 1.0 average for “Everybody Hates Chris” (1.1) and “All of Us” (1.0).
 
At 9 p.m. NBC led again with a 6.4 for “Heroes,” followed by a 5.1 for CBS for “Two and a Half Men” (5.5) and “Rules of Engagement” (4.8). Fox was third with a 4.8 for “24,” ABC fourth with a 4.1 for “Supernanny,” Univision fifth with a 1.5 for “Mundo de Fieras” and CW sixth with a 1.1 average for “Girlfriends” (1.1) and “The Game” (1.1).
 
CBS took over at 10 p.m. with a 5.5 for “CSI: Miami,” while ABC and NBC tied for second at 3.5, ABC for a “Building a Dream” Oprah Winfrey special and NBC for the premiere of “Donnellys.” Univision was fourth that hour with a 1.1 for “Cristina.”
 
CBS was first for the night among households, averaging an 8.8 rating and posting a 14 share. NBC was second at 8.2/13, Fox third at 6.9/10, ABC fourth at 6.2/10, Univision fifth at 2.0/3 and CW sixth at 1.7/3.