The Winter Olympics, starting on a Thursday this time around, dominated the night’s ratings action — though CBS’ “The Big Bang Theory” and “The Millers” and Fox’s “American Idol” held up well.

According to preliminary national estimates from Nielsen, the Sochi Games on NBC averaged a 5.8 rating/16 share in adults 18-49 and 19.6 million viewers overall during primetime, which featured early figure skating, snowboarding and women’s freestyle skiing action in advance of tonight’s Opening Ceremonies. Four years ago, the first night of action (on a Saturday) did a 7.5 prelim primetime average in 18-49.

That big number certainly helped boost Jay Leno’s final edition of “The Tonight Show,” which racked up its best overnight (9.2/22) in nearly five years. In the overnights, the Olympics did an 11.8 — the best Thursday for any network since the opening game of the NFL season on NBC last September.

Elsewhere, CBS’ “The Big Bang Theory” (5.0 rating/15 share in adults 18-49, 17.2 million viewers overall) lost some older viewers to the Olympics, but retained more than 95% of its young-adult audience from the previous week (5.2 in the nationals) and was a close finish to the Olympics for the 8 o’clock half-hour (5.0 vs. 5.3). Also holding up well was “The Millers” (2.7/8 in 18-49, 10.9 million viewers overall), which appears to be on par with last week, but both “The Crazy Ones” (1.7/5 in 18-49, 7.6 million viewers overall) and “Two and a Half Men” (1.8/5 in 18-49, 8.1 million viewers overall) were down about 10% from the previous week to series lows. At 10 p.m., “Elementary” (1.8/5 in 18-49, 9.3 million viewers overall) was off just a tick from last week.

Fox’s “American Idol” (3.0/9 in 18-49, 10.9 million viewers overall) was down 6% week to week (3% vs. its prelim score), again finishing well behind “The Big Bang Theory” but then topping “The Millers” at 8:30 (3.2 to 2.7 in 18-49, 11.6 million to 10.9 million in total viewers). “Rake” (1.1/3 in 18-49, 4.3 million viewers overall) continues to struggle behind it, dropping another two-tenths this time and down 35% from its not-so-hot premiere of Jan. 23 (1.7).

ABC’s “The Taste” (1.0/3 in 18-49, 3.2 million viewers overall) held nearly all of its (low) young-adult audience from last week, pulling even with Fox’s “Rake” in the 9:30 p.m. half-hour (both at 1.0). An encore “Shark Tank” closed things out (0.9/3 in 18-49, 3.3 million viewers overall).

CW’s “The Vampire Diaries” (0.9/3 in 18-49, 2.1 million viewers overall) was down from last week, but “Reign” held up (0.6/2 in 18-49, 1.7 million viewers overall) — an encouraging sign for its renewal prospects.

Preliminary 18-49 averages for the night: NBC, 5.8/16; CBS, 2.5/7; Fox, 2.1/6; ABC, 1.0/3; CW, 0.8/2.

In total viewers: NBC, 19.6 million; CBS, 10.4 million; Fox, 7.6 million; ABC, 3.2 million; CW, 1.9 million.