CBS’s “Survivor” continued its long slide last night with its 15th season debut, posting its worst fall premiere numbers ever, though the show still dominated its timeslot.

“Survivor: China” averaged a 4.9 adults 18-49 rating, according to Nielsen overnights, down 16 percent from a 5.8 for last spring’s most recent premiere. It was also way down from a 6.3 for its debut this time last year.

“Survivor” has been slipping for several cycles. Last spring was the show’s lowest-rated ever, though that mirrored spring viewership losses seen by many hits across the networks.

Still, “Survivor” seems likely to remain No. 1 in its 8 p.m. timeslot when the other broadcast competition premieres next week. Last night it still outpaced the combined total for the hour’s No. 2 and No. 3 shows, Fox’s “Are You Smarter Than a 5th Grader” and NBC’s “My Name Is Earl” repeat.

And among total viewers, “Survivor” averaged 15.1 million total viewers, which is pretty good for a show in its 15 season.

Meanwhile, CBS finished first for the night among viewers 18-49 with a 3.9 average overnight rating and an 11 share. Fox was second at 2.6/8, NBC third at 2.1/6, Univision fourth at 1.8/5, ABC fifth at 1.6/5 and CW sixth at 0.8/2.
 
CBS led each hour of the night, starting with a 4.9 at 8 p.m. for “Survivor.” Fox was second with a 2.3 for “Smarter,” NBC third with a 2.2 for an hour of “Earl” repeats, ABC fourth with a 1.4 for a repeat of “Ugly Betty,” Univision fifth with a 1.2 for “Amar sin Limites” and CW sixth with a 0.6 for the first hour of a “Beauty and the Geek” repeat.
 
At 9 p.m. CBS led again with a 3.9 for a repeat of “CSI,” followed by Fox with a 2.9 for “Don’t Forget the Lyrics.” NBC was third with a 2.4 for an hour of “The Office” repeats, Univision fourth with a 2.1 for the first hour of the special “Latin Grammy Celebra: Marco Antonio Solis,” ABC fifth with a 1.9 for a “Grey’s Anatomy” rerun and CW sixth with a 0.9 for the second half of its “Beauty and the Geek” repeat.
 
At 10 p.m. CBS was first with a 2.9 for a repeat of “Without a Trace,” with Univision second with a 2.0 for the second half of its “Latin Grammy” special. NBC was third with a 1.6 for a repeat of “ER” and ABC fourth with a 1.4 for a “Men in Trees” rerun.
 
Among households, CBS comfortably finished first for the night with an 8.6 average overnight rating and a 14 share, followed by Fox at 5.1/8. ABC was third at 3.4/6, NBC fourth at 3.2/5, Univision fifth at 2.2/4 and CW sixth at 1.3/2.