It didn’t face originals of the night’s top shows, but Fox’s “American Idol” had an impressive Thursday premiere, matching last year’s score and nearly equaling the deliveries of ABC, CBS and NBC for its two-hour block.

Early ratings weren’t available, meanwhile, for Oprah Winfrey’s interview with Lance Armstrong, which aired from 9 to 10:30 p.m. on cabler OWN and likely stole some viewers away from the broadcast nets.

According to preliminary national estimates from Nielsen, “American Idol” averaged a 5.6 rating/15 share in adults 18-49 and 16.2 million viewers overall, holding 93% of its opening-night demo rating (6.0) for the show’s best retention from its first to second nights in four years. Wednesday’s premiere score had come in nearly 20% lower than its year-ago premiere.

From 8 to 10 p.m., the 5.6 rating in 18-49 for “Idol” nearly matched the combined deliveries in the time period for ABC, CBS and NBC (5.8). And in adults 18-34, its 4.8 rating did top the combined scores of Fox’s chief rivals (4.5).

And it’s in the 18-34 demo that Fox got its best news, as “Idol” surged by 17% vs. its premiere Thursday score of a year ago.

The only series this season to produce a higher same-night 18-49 rating than the first two nights of “American Idol” is CBS’ “The Big Bang Theory.” The highest score for NBC’s “The Voice” in its fall cycle was a 4.9 (for its finale).

“Idol” will air another two-hour installment next week, with “Glee” returning on Jan. 31. “The Big Bang Theory” and “Two and a Half Men” — the music contest’s chief competition in its regular 8 p.m. hour and Thursday’s two top-rated programs — return with new episodes on Jan. 31.

Elsewhere, ABC ran second despite another weak showing kicking off the night for lame-duck drama “Last Resort” (1.0/3 in 18-49, 5.0 million viewers overall). It was followed by “Grey’s Anatomy” (2.9/7 in 18-49, 8.7 million viewers overall), which matched its season low but ranked second to “Idol” in demos for the 9 o’clock hour, and “Scandal” (2.6/7 in 18-49, 7.9 million viewers overall), which was down from its series highs of last week but again was the hour’s top series in 18-49; in fact, the show has produced its top four 18-49 scores with its last four telecasts.

CBS did very well with encores of “The Big Bang Theory” (3.3/10 in 18-49, 11.9 million viewers overall) and “Two and a Half Men” (2.4/6 in 18-49, 9.1 million viewers overall), placing second to “Idol.” The comedies were followed by repeats of dramas “Person of Interest” (1.6/4 in 18-49, 9.4 million viewers overall) and “Elementary” (1.4/4 in 18-49, 7.0 million viewers overall).

NBC started sluggishly with “30 Rock” (1.3/4 in 18-49, 3.5 million viewers overall) but spiked some at 8:30 p.m. with the time-period premiere of “Parks and Recreation” (1.9/5 in 18-49, 3.9 million viewers overall), which logged the slot’s best comedy score in 18-49 since last March. “Parks” hasn’t done a higher 18-49 rating since November 2011.

At 9, “The Office” (2.1/5 in 18-49, 4.2 million viewers overall) nearly matched its averages of last week despite the additional competition from “American Idol,” but newcomer “1600 Penn” lagged at 9:30 p.m. (1.2/3 in 18-49, 3.0 million viewers overall), down 25% from its regular-slot premiere of last week. And at 10, “Rock Center with Brian Williams” (1.2/3 in 18-49, 4.4 million viewers overall) was up for a second straight week for its best numbers since Nov. 1.

CW’s winter premiere of “The Vampire Diaries” (1.4/4 in 18-49, 2.9 million viewers overall) topped the show’s four most recent originals, ranking second for the 8 o’clock hour among women 18-34 (2.2/7). It was followed by another repeat of new Monday drama “The Carrie Diaries” (0.5/1 in 18-49, 1.2 million viewers overall).

Preliminary 18-49 averages for the night: Fox, 5.6/15; ABC, 2.2/6; CBS, 1.9/5; Univision, 1.6/4; NBC, 1.5/4; CW, 0.9/2.

In total viewers: Fox, 16.2 million; CBS, 9.0 million; ABC, 7.2 million; NBC and Univision, 3.9 million; CW, 2.0 million.