NBC’s coverage of the Winter Olympics dominated once again Wednesday, while Fox’s “American Idol” tumbled to its lowest score ever on the night — beaten head-to-head in total viewers by CBS’ “Criminal Minds” for the first time.

In latenight, meanwhile, NBC’s “Tonight Show Starring Jimmy Fallon” nearly matched its preliminary Tuesday numbers and again easily beat its rivals.

According to preliminary national estimates from Nielsen, the Sochi Games on NBC averaged a 5.0 rating/15 share in adults 18-49 and 20.1 million viewers overall during primetime, down about 10% week to week as the Olympics tend to lose some steam down the stretch. Wednesday’s action, which included figure skating, men’s alpine skiing and women’s bobsled, was off vs. the comparable night four years ago in Vancouver by 9% in the demo but just 2% in total viewers.

At Fox, “American Idol” averaged a 2.6 rating/8 share in adults 18-49 and 9.9 million viewers overall, down about 20% week to week and its lowest numbers ever for a regular Wednesday episode. Still, it was the top-rated series of the night in 18-49, 25-54 (3.6/9) and other demos.

Wednesday’s installment, which featured the top 10 boys singing, performed in line with the previous night’s episode with the top 10 girls (2.7/8 in 18-49, 9.6 million).

CBS’ “Criminal Minds,” though, appears to have pulled ahead of “Idol” head-to-head in total viewers for the first time (9.9 million vs. 9.8 million in the prelims). It was preceded by a special repeat of “Hawaii Five-0” (0.9/3 in 18-49, 5.6 million viewers overall) and followed at 10 p.m. by “CSI” (2.0/6 in 18-49, 9.6 million viewers overall). Wednesday marked the first time during the Olympics that the Eye had aired any of its scripted hits.

ABC went with repeats of “The Middle” (1.0/3 in 18-49, 4.2 million viewers overall), “Suburgatory” (0.7/2 in 18-49, 3.0 million viewers overall) and “Modern Family” (1.2/4 in 18-49, 4.2 million viewers overall) and then the finale of “Super Fun Night” (0.9/3 in 18-49, 2.7 million viewers overall). An encore “Nashville” finished things off (0.5/1 in 18-49, 1.8 million viewers overall).

CW aired repeats of “Arrow” (0.3/1 in 18-49, 1.0 million viewers overall) and “The Tomorrow People” (0.2/1 in 18-49, 0.8 million viewers overall).

In latenight, “The Tonight Show Starring Jimmy Fallon” averaged a 5.2 household rating/15 share in Nielsen’s metered-market overnights from midnight to 1 a.m., making it “Tonight’s” biggest Wednesday by this measure in six years. It again beat the combined averages of 11:35 p.m. talkshows “Late Show With David Letterman” on CBS (2.2/6) and “Jimmy Kimmel Live” on ABC (1.6/4).

And in the 25 markets with Local People Meters, “Tonight” drew the show’s highest adults 18-49 rating (2.2/12 share) on a Wednesday in nearly 10 years — double the combined scores of Letterman (0.6) and Kimmel (0.5).

Preliminary 18-49 averages for the night: NBC, 5.0/15; Fox, 2.6/8; CBS, 1.8/5; ABC, 0.8/2; CW, 0.3/1.

In total viewers: NBC, 20.1 million; Fox, 9.9 million; CBS, 8.4 million; ABC, 2.9 million; CW, 0.9 million.