In a special head-to-head battle between two of television’s most popular shows, Fox’s “American Idol” beat out ABC’s “Lost” on Wednesday, with the programs combining for 45% of the available young-adult audience in the night’s leadoff hour, according to preliminary nationals from Nielsen.

“Lost” (7.3 rating/18 share in adults 18-49, 20 million viewers overall) was slightly below its recent series-high ratings but impressively put up more gaudy numbers opposite night two of the “American Idol” season premiere (11.1/27 in adults 18-49, 26.4 million viewers overall). And although below its averages of Tuesday, “Idol” remains off to its hottest start to date.

The same nets staged a drama battle at 9, with ABC vet “Alias” (5.8/14 in adults 18-49, 14 million viewers overall) winning the hour over Fox’s series premiere of “Point Pleasant” (5.4/12 in adults 18-49, 11.7 million viewers overall). The significant sampling for “Pleasant” should help the spooky drama as it slides into its tough regular Thursday-at-9 slot tonight.

Elsewhere, NBC’s “Law & Order” won at 10 (4.7/12 in adults 18-49, 15.1 million viewers overall) over ABC’s competitive “Wife Swap” (4.4/11 in adults 18-49, 9.9 million viewers overall) and a repeat of CBS’ “CSI: NY” (3.8/10 in adults 18-49, 10.7 million viewers overall). Also performing well was CBS laffer “King of Queens” at 9 (4.8/11 in adults 18-49, 13 million viewers overall), although lead-out “Center of the Universe” fell off to a 3.8/9 in the demo and 10.4 million viewers overall.

Preliminary 18-49 averages for the night: Fox, 8.2/20; ABC, 5.8/14; CBS, 3.2/8; NBC, 3.2/8; WB, 1.1/3; UPN, .9/2.

In total viewers: Fox, 19 million; ABC, 14.5 million; CBS, 10.3 million; NBC, 10.1 million; WB, 2.8 million; UPN, 2.2 million.