In what figures to be a familiar refrain over the next two weeks, NBC’s coverage of the London Games crushed everything else in primetime Monday -, with its averages topping those of the six broadcast networks combined.

According to preliminary national estimates from Nielsen, the Olympics averaged a 10.5 rating/28 share in adults 18-49 and 31.4 million viewers overall from 8 to 11 p.m., with the night’s final averages subject to change due to any atypical start or stop times. In primetime, though, that demo tally exceeded the combined output of (in descending order of strength) Univision, Fox, CBS, ABC, Telemundo and CW. Action on Monday featured swimming, men’s gymnastics, men’s diving and beach volleyball. Through four nights, NBC remained up nicely vs. the 2008 Beijing Games, by nearly 10% in adults 18-49 and by nearly 15% in total viewers.

Univision ranked second among young adults, led by novelas ”La Que No Podia Amar” at 10 (1.6/4 in 18-49, 4.4 million viewers overall) and ”Abismo de Pasion” at 9 (1.3/3 in 18-49, 3.6 million viewers overall).

ABC was the only Big Four rival to NBC offering original fare on Monday, but ”Bachelor Pad” (1.1/3 in 18-49, 3.5 million viewers overall) was down about 25% from its week-earlier premiere, and rookie ”The Glass House” remains on the air despite continued tiny ratings (lowest-yet 0.6/2 in 18-49, 1.7 million viewers overall).

Fox aired back-to-back encores of ”Hell’s Kitchen” at 8 (1.1/3 in 18-49, 2.8 million viewers overall) and 9 (1.2/3 in 18-49, 2.9 million viewers overall). And CBS aired repeats of its regular scripted Monday series: ”How I Met Your Mother” (0.9/3 in 18-49, 3.4 million viewers overall), ”2 Broke Girls” (1.0/3 in 18-49, 3.5 million viewers overall), ”Two and a Half Men” (1.1/3 in 18-49, 4.2 million viewers overall), ”Mike and Molly” (1.1/3 in 18-49, 3.9 million viewers overall) and ”Hawaii Five-0” (0.9/2 in 18-49, 3.9 million viewers overall).

Preliminary 18-49 averages for the night: NBC, 10.5/28; Univision, 1.3/4; Fox, 1.1/3; CBS, 1.0/3; ABC, 0.9/3; CW, 0.2/0.

In total viewers: NBC, 31.4 million; CBS, 3.8 million; Univision, 3.6 million; Fox, 2.9 million; ABC, 2.8 million; CW, 0.4 million.