In one of their final scheduled firstrun pairings for a while, “American Idol” and “House” scored more monster numbers for Fox on Tuesday night, as the net outscored the combined deliveries of the other major broadcast nets.

According to preliminary nationals from Nielsen, “American Idol” dominated the opening hour with an 11.0 rating/27 share in adults 18-49 and 28.1 million viewers overall — beating its ABC-CBS-NBC combined competition by 80% in 18-49 rating. Still, the megahit was off by a little more than 15% compared to the same night a year ago. “House” followed with a big outing at 9 (8.6/20 in 18-49, 22.5 million viewers overall), more than doubling its closest competitor.

With “House” running out of original episodes due to the writers strike, Fox is shifting its sked in a couple of weeks. “House” repeats will play on Mondays, while other series, including returning reality hit “Hell’s Kitchen,” take over the 9 o’clock slot on Tuesday.

Elsewhere on the night, NBC ran second thanks to “The Biggest Loser” (3.3/8 in 18-49, 8.3 million viewers overall) and a repeat of “Law & Order: Special Victims Unit” (slot-leading 2.9/8 in 18-49, 9.4 million viewers overall). “Loser” built sharply from its first hour to its second, peaking with a 4.2/10 in the demo and 10.4 million viewers overall in the 9:30 half-hour.

CBS aired repeats of “NCIS” (2.0/5 in 18-49, 11.7 million viewers overall) and “The Unit” (1.7/4 in 18-49, 4.9 million viewers overall) and ran second to “SVU” at 10 o’clock with a special firstrun edition of “48 Hours Mystery” (2.4/6 in 18-49, 7.8 million viewers overall).

ABC’s best performer on a very quiet night was “According to Jim” at 9 o’clock (2.0/5 in 18-49, 5.9 million viewers overall), while CW was paced by “One Tree Hill” (1.3/3 in 18-49, 2.8 million viewers overall), which ran third in its 9 o’clock hour among persons 12-34 (1.8/5).

Preliminary 18-49 averages for the night: Fox, 9.8/24; NBC, 3.2/8; CBS, 2.0/5; Univision, 1.7/4; ABC, 1.4/4; CW, 0.9/2.

In total viewers: Fox, 25.3 million; CBS, 8.9 million; NBC, 8.7 million; ABC, 5.1 million; Univision, 3.4 million; CW, 2.2 million.