NBC, behind ”America’s Got Talent,” topped the ratings race on an atypical Wednesday night that included more than an hour of commercial-free coverage from the Republican National Convention as well as some local-market preemptions for preseason football on ABC, CBS and NBC.

According to preliminary national estimates from Nielsen that are subject to more revision than usual in the finals, NBC won Wednesday among young adults thanks to the 9 o’clock-hour edition of ”America’s Got Talent” (2.5/7 in 18-49, 9.1 million viewers overall), which followed a repeat at 8 (1.4/5 in 18-49, 5.8 million viewers overall). The Peacock also led the Big Three’s coverage of the convention in the 10 o’clock hour (1.3/4 in 18-49, 4.5 million viewers overall); and because the live event spilled past 11 p.m. ET, ratings for the 8 o’clock hour on the West Coast could also be affected for NBC as well as ABC and CBS.

Fox, the only major net not airing the RNC, went with a two-hour ”So You Think You Can Dance” (1.6/5 in 18-49, 4.3 million viewers overall), which was up a tick week to week.

At CBS, ”Big Brother” was on the high side for a Wednesday (2.3/7 in 18-49, 6.7 million viewers overall) and was followed by a repeat ”Criminal Minds” (1.3/4 in 18-49, 5.5 million viewers overall) and news coverage from the convention in Florida (0.6/2 in 18-49, 2.8 million viewers overall).

And ABC aired repeats of ”The Middle” (1.0/3 in 18-49, 4.2 million viewers overall), ”Suburgatory” (1.1/3 in 18-49, 3.9 million viewers overall), ”Modern Family” (1.3/4 in 18-49, 4.0 million viewers overall) and a second ”Suburgatory” (1.1/3 in 18-49, 3.2 million viewers overall), before closing with RNC coverage (0.7/2 in 18-49, 2.6 million viewers overall).

CW’s ”Oh Sit” (0.4/1 in 18-49, 1.3 million viewers overall) held steady in demos and gained in total viewers week-to-week. It was followed by an encore of ”Supernatural” (0.3/1 in 18-49, 1.0 million viewers overall).

Preliminary 18-49 averages for the night: NBC, 1.7/5; Fox, 1.6/5; Univision, 1.5/4; CBS, 1.4/4; ABC, 1.0/3; CW, 0.4/1.

In total viewers: NBC, 6.5 million; CBS, 5.0 million; Fox, 4.3 million; Univision, 3.7 million; ABC, 3.4 million; CW, 1.1 million.