Fox has rolled to another Tuesday primetime ratings victory behind dominant showings from both “American Idol” and “House,” according to preliminary nationals from Nielsen.

“American Idol” (11.0 rating/31 share in adults 18-49, 27.5 million viewers overall) easily topped the combined scores of the other five broadcast nets in the 8 o’clock hour. One of “Idol’s” victims was night two of NBC’s unscripted skein “Celebrity Cooking Showdown” (1.1/3 in 18-49, 3.4 million viewers overall), which placed sixth among broadcast nets — lagging both the WB and Spanish-language Univision.

“House” then rolled at 9 with one of its best deliveries to date (9.1/22 in 18-49, 23.3 million viewers overall), beating ABC, CBS and NBC combined.

CBS was a solid second with original episodes of “NCIS” (3.6/10 in 18-49, 15.6 million viewers overall) and “The Unit” (4.3/10 in 18-49, 15.4 million viewers overall), while ABC’s weak night was led by 10 o’clock drama “Boston Legal” (2.7/7 in 18-49, 9.3 million viewers overall).

Preliminary 18-49 averages for the night: Fox, 10.0/26; CBS, 3.7/10; NBC, 2.3/6; ABC, 2.1/5; WB, 1.5/4; UPN, 1.0/3.

In total viewers: Fox, 25.4 million; CBS, 14.0 million; ABC, 6.4 million; NBC, 5.7 million; WB, 3.2 million; UPN, 2.2 million.