CBS’s “Survivor” continued its slow fade last night, posting its lowest-ever rating for a season premiere.

The show averaged a 5.8 among adults 18-49, according to Nielsen overnights, down 8 percent from last fall’s 6.3 average for its premiere.

Still, the long-running reality show maintained first place in what’s become a very competitive timeslot. During “Survivor’s” two-month hiatus, competing shows “Ugly Betty” on ABC and “My Name is Earl” and “The Office” on NBC hit season or near-season highs.

And last night all four programs averaged a 4.2 rating or above, which is quite rare these days on broadcast.

“Survivor” is coming off of its lowest-rated season and is now in its 14th incarnation. While it’s not the powerhouse it once was, it remains a top show for CBS in the demo, and no other reality show has demonstrated such impressive staying power for so long.

Meanwhile last night, ABC’s Thursday lineup continued its impressive ratings surge. At 8 p.m., “Ugly Betty” matched last week’s 4.7 rating, its second-best of the season.

“Grey’s Anatomy” posted its second-best rating of the season, a 10.7, for the first of a three-parter, just 0.3 behind its season debut in September. And “Men in Trees” hit a series high for the third straight week with a 4.1, though that is expected to adjust downward when final ratings are released as “Grey’s” ran slightly longer than its 10 p.m. end-time.

ABC finished first for the night among viewers 18-49 with a 6.5 average rating and a 16 share. CBS was second at 5.6/14, NBC third at 4.0/10, Univision fourth at 1.8/5, Fox fifth at 1.8/4 and CW sixth at 1.5/4.
 
A different network led each hour over the course of the night, and CBS started on top with a 5.8 rating at 8 p.m. for “Survivor.” ABC was second with a 4.7 for “Betty,” NBC third with a 4.3 average for “Earl” (4.2) and “Office” (4.4), and Univision fourth with a 2.3 for “La Fea Mas Bella.” Fox was fifth with a 1.9 average for “’Til Death” (2.0) and “The War at Home” (1.9) and CW sixth with a 1.8 for “Smallville.”
 
It was ABC’s turn on top at 9 p.m., as “Grey’s” posted 10.7 rating, the night’s top show among 18-49s. CBS fell to second with a 6.8 for “CSI,” with NBC third with a 2.8 average for “Scrubs” (3.1) and “30 Rock” (2.5) and Univision fourth with a 1.7 for “Mundo de Fieras.” Fox finished fifth that hour with a 1.6 for “The O.C.” and CW sixth with a 1.2 for “Supernatural.”
 
At 10 p.m. NBC jumped into the lead with a 4.8 rating for “ER.” ABC and CBS tied for second at 4.1, ABC for “Men in Trees” and CBS for “Shark,” with Univision fourth with a 1.4 for “Aqui y Ahora.”
 
CBS grabbed a first-place finish for the night among households, averaging an 11.0 rating and a 17 share. ABC was second at 10.5/16, NBC third at 5.8/9, Fox fourth at 2.8/4, Univision fifth at 2.3/4 and CW sixth at 2.3/3.