The premiere of CBS’s “Viva Laughlin” last night was more than a little off-key. It hit a decidedly sour note.

The new musical drama about a singing casino owner, dismissed by critics and media buyers as one of the season’s worst new shows, lost nearly two-thirds of its lead-in and finished last in its timeslot despite receiving a plum post-“CSI” debut.

“Laughlin” averaged a 2.4 rating in adults 18-49, according to Nielsen overnights, which measure live and same-day digital video recorder playback viewing. That was off 63 percent from lead-in “CSI,” which averaged a 6.4.

And it was down 41 percent from usual 10 p.m. timeslot occupant “Without a Trace,” which has averaged 4.1 in three outings.

Among total viewers the story wasn’t much better. “Laughlin” averaged 8.8 million, off 58 percent from “CSI’s” 20.8 million. “Trace” has averaged 15.1 million viewers in the slot.

CBS debuted “Laughlin” behind “CSI,” its top-rated show, hoping to give the new program a lift before it takes over its usual Sunday 8 p.m. spot, where it’s expected to struggle opposite ABC’s “Extreme Makeover: Home Edition” and NBC’s “Sunday Night Football.”

CBS likely would have recorded its third Thursday victory in four weeks were it not for “Laughlin’s” low ratings, on a night when Fox’s American League Championship Series drained viewers from both ABC and NBC. Instead, CBS finished 0.1 behind ABC for the night, even as its “Grey’s Anatomy” hit a season low.

ABC was first for the night among viewers 18-49 with a 4.5 average overnight rating and a 12 share, edging CBS’s 4.4/12. NBC was third at 3.7/10, Fox fourth at 3.6/10, Univision fifth at 1.7/4 and CW sixth at 1.6/4.

As a reminder, viewership for the live ALCS game may not be accurate, as overnight data measures timeslots and not actual program data. Final ratings out later today could adjust significantly.
 
CBS began the night in the lead with a 4.5 at 8 p.m. for “Survivor,” with ABC and Fox tied for second at 3.1, ABC for “Ugly Betty” and Fox for the first hour of its ALCS game five between Boston and Cleveland. NBC was fourth with a 2.7 average for “My Name is Earl” (2.7) and “30 Rock” (2.6), CW fifth with a 2.0 for “Smallville” and Univision sixth with a 1.1 for “Amar sin Limites.”
 
At 9 p.m. ABC took the lead with a 7.1 for “Grey’s,” while CBS slipped to second with a 6.4 for “CSI.” NBC was third with a 4.4 for “The Office,” Fox fourth with a 3.5 for baseball, Univision fifth with a 2.3 for “Destilando Amor” and CW sixth with a 1.3 for “Supernatural.”
 
Fox took the lead at 10 p.m. with a 4.4 for another hour of baseball, followed by NBC with a 4.0 for “ER.” ABC was third with a 3.3 for “Big Shots,” CBS fourth with a 2.4 for “Laughlin” and Univision fifth at 1.7 for "Aqui y Ahora."
 
Among households, CBS led the night with a 9.0 average overnight rating and a 14 share. ABC was second at 8.2/13, Fox third at 8.0/13, NBC fourth at 5.3/8, CW fifth at 2.5/4 and Univision sixth at 1.9/3.