More ratings highs for “Lost” and a great tune-in for the two-hour season premiere of “Alias” helped ABC dominate Wednesday, according to preliminary nationals from Nielsen, drawing its largest overall audience on the night in more than two years.

“Lost” kicked things off with huge numbers (8.3 rating/21 share in adults 18-49, 21.5 million viewers overall), including the highest demo rating for an 8 o’clock drama on any net in nearly nine years. It matched the demo deliveries in the hour of CBS, NBC and Fox combined.

Then from 9 to 11, “Alias” (6.7/16 in adults 18-49, 16.0 million viewers overall) established primetime highs as it kicked off its fourth season in style. It led both hours in 18-49, with its 10-11 p.m. scores (6.2/15 in adults 18-49, 14.4 million viewers overall) impressively beating both NBC’s original “Law & Order” (4.5/11 in adults 18-49, 14.3 million viewers overall) and CBS’ firstrun “CSI: NY” (4.4/11 in adults 18-49, 12.7 million viewers overall).

These repped series-low scores for “CSI: NY,” which ran third for its hour for the first time.

Elsewhere, CBS’ “King of Queens” was runnerup at 9 (4.3/10 in adults 18-49, 11.4 million viewers overall), while Fox’s “Nanny 911” (4.1/9 in adults 18-49, 9.7 million viewers overall) hit new highs in the 9 o’clock hour.

At 8, NBC’s premiere of “Sports Illustrated Swimsuit Model Search” (2.8/7 in adults 18-49, 7.0 million viewers overall) improved upon the net’s average in the time period, about on par with Fox’s second-place comedies in the hour.

Preliminary 18-49 averages for the night: ABC, 7.3/18; CBS, 3.7/9; NBC, 3.6/9; Fox, 3.5/8; UPN, 1.2/3; WB, 1.2/3.

In total viewers: ABC, 17.9 million; CBS, 11.6 million; NBC, 11.1 million; Fox, 8.0 million; UPN, 2.9 million; WB, 2.6 million.