Fast National ratings for Thursday, Jan. 22, 2009.

The first post-William Petersen episode of "CSI: Crime Scene Investigation" saw a ratings drop and lost the 18-49 demographic to "Grey's Anatomy," but it remained TV's most watched show on Thursday night.

ABC won the night in the 18-49 demo, doing a 3.9 rating. CBS was second in the key age range with a 3.3 rating, followed closely by the 3.1 rating for NBC and FOX's 2.7 rating. The CW's 1.4 rating was fifth.

Overall, though, CBS averaged an estimated 12.8 million viewers and an 8.0 rating/13 share. ABC was second with a 7.0/11. FOX was third with a 5.4/8, beating NBC's 4.4/7 and the 2.0/3 for The CW.

Get this: FOX actually won the 8 p.m. hour on a Thursday, as the time slot premiere of "Bones" paid immediate dividends with a 6.1/10. CBS was second with a repeat of "NCIS," which topped the 5.1/8 for "Ugly Betty" on ABC. NBC's "My Name Is Earl" and "Kath & Kim" finished fourth for the hour, topping the 2.3/4 for "Smallville" on The CW.

CBS moved into first place at 9 p.m. with a 10.6/16 for "CSI." ABC's "Grey's Anatomy" was second with a 9.4/13. Another episode of "Bones" on FOX took a hit, but still beat "The Office" (5.0/8) and "30 Rock" (3.9/6) on NBC. The CW's "Supernatural" was fifth.

"Eleventh Hour" won the 10 p.m. hour for CBS with a 7.9/13. ABC's "Private Practice" was second with 6.5/11, better than the 5.1/9 for "E.R." on NBC.

All ratings information comes from preliminary Fast National Nielsen data, which includes live and same-day DVR viewing. All numbers are subject to change.