Although NBC outperformed it in two hours of Thursday, CBS came away with another demo victory on the night behind a dominant showing by “CSI,” according to preliminary nationals from Nielsen.

From 9 to 10, an original episode of “CSI” ruled as the night’s top-rated program (9.5 rating/23 share in adults 18-49, 27.2 million viewers overall), more than doubling NBC’s hour of “Will & Grace” (4.4/11 in adults 18-49, 9.5 million viewers overall for one original and one repeat seg).

“ER” also had a strong showing at 10 (8.3/21 in adults 18-49, 18.5 million viewers overall), topping the combined demo scores of CBS’ “Without a Trace” (6.1/16 in adults 18-49, 18.7 million viewers overall) and ABC’s “Primetime” (2/5 in adults 18-49, 6.3 million viewers overall). “Trace” edged out “ER” in total viewers, although the medical drama pulled ahead at 10:30.

In the night’s opening hour, NBC’s combo of “Joey” (5/14 in adults 18-49, 12.4 million viewers overall) and a special firstun “Committed” (4.7/12 in adults 18-49, 11 million viewers overall) kept the net on top over Fox’s “The OC” (3.3/8 in adults 18-49, 7.6 million viewers overall) and week two of CBS unscripted skein “Wickedly Perfect” (3.2/9 in adults 18-49, 9.6 million viewers overall). “Wickedly” was up a bit week-to-week, filling the slot until “Survivor” returns Feb. 17.

Preliminary 18-49 averages for the night: CBS, 6.2/16; NBC, 5.8/15; Fox, 2.6/7; UPN, 2.0/5; ABC, 1.8/3; WB, 1.1/3.

In total viewers: CBS, 18.5 million; NBC, 13.2 million; Fox, 5.8 million; UPN, 5.8 million; ABC, 5.4 million; WB, 2.8 million.