It will soon face tougher competition from Fox’s “American Idol,” but ABC’s “Wipeout” had an impressive premiere Thursday, hitting some series highs and winning its hour in demos. CBS’ “The Big Bang Theory” and ABC’s “Grey’s Anatomy” were the night’s top shows among young adults.

Overall, ABC and CBS were the clear leaders on a night when NBC and Fox were mostly in repeat mode; the Alphabet led in 18-49, with CBS close behind and victorious among adults 25-54 and total viewers. “American Idol” and NBC’s new six-comedy Thursday will make the night more interesting on Jan. 20.

According to preliminary nationals from Nielsen, the winter premiere of “Wipeout,” a snowy version of the popular summer reality hit, averaged a hearty 3.7 rating/11 share in adults 18-49 and 11.6 million viewers overall in the 8 o’clock hour — achieving series highs in teens, kids and total viewers and producing the net’s best regular-program 18-49 result in the timeslot since the series premiere of “FlashForward” in September 2009.

“Wipeout” edged out in 18-49 the combined delivery of CBS comedies “The Big Bang Theory” (4.4/13 in 18-49, 14.0 million viewers overall) and “Bleep My Dad Says” (2.9/8 in 18-49, 10.9 million viewers overall), with the Eye’s “Big Bang” — the night’s No. 1 show in 18-49 — winning at 8 and the Alphabet surging ahead at 8:30. “Wipeout” opened up a wide advantage among persons under 50, drawing roughly 7.6 million to 5.6 million for the CBS comedies, which still led the hour in total viewers.

At 9, ABC’s “Grey’s Anatomy” (4.2/11 in 18-49, 11.7 million viewers overall) was up slightly vs. its last original episode to win the hour in 18-49 over CBS’ “CSI” (3.3/9 in 18-49, 14.2 million viewers overall), which topped the 18-49 score of its previous three firstrun episodes; the crime drama also placed a close second to “Grey’s” in 25-54 while winning the hour in total viewers.

And closing out the night, CBS’ “The Mentalist” (3.0/9 in 18-49, 14.8 million viewers overall) bested ABC’s “Private Practice” (2.8/8 in 18-49, 7.8 million viewers overall, with the former standing as the night’s most-watched program overall.

Elsewhere, Fox continues to produce modest numbers for its limited-run, multi-night gameshow “Million Dollar Money Drop” (1.4/4 in 18-49, 4.6 million viewers overall), which was followed by a repeat of “Bones” (1.0/3 in 18-49, 3.4 million viewers overall).

And NBC saw similar demo deliveries on the night with its encores of comedies “Community” (1.0/3 in 18-49, 3.0 million viewers overall), “30 Rock” (1.3/4 in 18-49, 3.2 million viewers overall), “The Office” (1.7/5 in 18-49, 4.0 million viewers overall), “Outsourced” (1.3/3 in 18-49, 3.2 million viewers overall), a second “Outsourced” at 10 p.m. (1.0/3 in 18-49, 2.2 million viewers overall) and a second “Office” at 10:30 p.m. (1.2/3 in 18-49, 2.3 million viewers overall).

CW aired repeats of “The Vampire Diaries” (0.5/2 in 18-49, 1.4 million viewers overall) and “Nikita” (0.5/1 in 18-49, 1.4 million viewers overall).

Preliminary 18-49 averages for the night: ABC, 3.6/10; CBS, 3.4/9; NBC, Fox and Univision, 1.2/3; CW, 0.5/1.

In total viewers: CBS, 13.8 million; ABC, 10.3 million; Fox, 4.0 million; Univision, 3.3 million; NBC, 3.0 million; CW, 1.4 million.