Fast National ratings for Thursday, Sept. 21, 2006

ABC loudly announced its arrival as a competitor on Thursday, as "Grey's Anatomy" unseated "CSI" as the night's top show -- at least for this week -- and helped the network claim a share of the ratings crown.

For the night, ABC averaged an 11.2 rating/18 share. CBS was a close second at 11.0/17 and actually won the night among total viewers with 18.08 million to ABC's 17.31 million. NBC came in third with a 7.4/12. FOX, 2.9/5, finished fourth, and The CW trailed with a 1.6/2.

ABC claimed an outright victory among adults 18-49 with a 7.2 rating. CBS, 6.0, took second in the demographic advertisers love most, while NBC came in third with a solid 4.8. There was a substantial drop to fourth-place FOX, 1.6, and The CW, which posted a 1.0.

"Survivor: Cook Islands" put CBS on top at 8 p.m. with a 9.8/16. A "Grey's Anatomy" clip show on ABC was a strong second at 9.2/15. NBC was third with season premieres of "My Name Is Earl," 5.8/10, and "The Office," 5.7/9 (which actually built on its lead-in a little in total viewers and 18-49). "'Til Death," 3.9/6, and "Happy Hour," 3.0/5, were fourth for FOX. The CW went with a "Smallville" rerun.

At 9 p.m., the "Grey's Anatomy" season premiere, 15.7/23, scored a rather shocking win over CBS' "CSI," 13.5/20, which has dominated the timeslot for several years. "Deal or No Deal" was a distant third for NBC at 6.5/10. "Celebrity Duets" slumped to a 2.4/4 for FOX. A "Supernatural" rerun on The CW trailed.

Another medical drama, NBC's "ER," won the 10 p.m. hour with a 10.0/16. The premiere of "Shark" on CBS averaged 9.8/16. ABC's "Six Degrees" lost a big chunk of its lead-in to finish at 8.6/14.

Ratings information is taken from fast national data, which includes live and same-day DVR viewing. All numbers are preliminary and subject to change.