Fox controlled Wednesday’s primetime ratings race with a two-hour episode that contributed to some series lows on the other networks. Meanwhile, though down a bit more again this year, CBS opened the 24th edition of ”Survivor” to good numbers.

According to preliminary national estimates, “American Idol” averaged a 6.0/16 in 18-49 and 18.6 million viewers overall from 8 to 10 p.m., on par with last week’s hourlong episode and easily the night’s No. 1 program in all categories. In adults 18-49, “Idol” won its opening hour over “Survivor” by 7 shares, topped “Modern Family” by 5 shares at 9 o’clock and then surged to a 9-share advantage at 9:30 when CBS’ “Criminal Minds” was runner-up. If “Idol” edges up to a 6.1 in the nationals, it will edge out the Monday delivery of NBC’s “The Voice” to rank as television’s No. 1 show among young adults for the week.

CBS kicked off ”Survivor: One World” with a 3.0/8 in 18-49 and 10.7 million viewers overall, down from last winter’s premiere (3.2 in the demo) but still a solid second-place finisher to ”Idol” in the 8 o’clock hour. It was followed by ”Criminal Minds” at a season low (3.0/7 in 18-49, 11.9 million viewers overall), but ”CSI” edged up week to week to win at 10 (2.7/7 in 18-49, 11.1 million viewers overall) as auds tuned in to see the premiere of Elizabeth Shue as a regular cast member. For the night, CBS ran second in 18-49, 25-54 and total viewers.

At ABC, ”The Middle” (2.5/7 in 18-49, 8.1 million viewers overall) and ”Suburgatory” (2.4/6 in 18-49, 6.9 million viewers overall) were down a bit week to week and at season-low levels for a regular original. Similarly at the shallow end of the pool were ”Modern Family” (4.7/12 in 18-49, 11.2 million viewers overall) and ”Happy Endings” (2.5/6 in 18-49, 5.8 million viewers overall), which had to do battle with ”American Idol” this week and thus dipped more week to week than the net’s opening-hour comedies. And at 10, ”Revenge,” despite a key episode in the soap’s plotline, edged down slightly week to week (2.4/6 in 18-49, 7.6 million viewers overall), placing second in most categories and first among the broadcasters in adults 18-34 (1.9/6).

The Alphabet was the only major network to post gains vs. its performance on the comparable night a year ago.

NBC’s ”Whitney” (1.6/5 in 18-49, 4.5 million viewers overall) ticked up week to week, drawing its largest overall audience in five weeks, but ”Are You There, Chelsea” went a bit in the other direction (1.4/4 in 18-4, 3.5 million viewers overall). Also down week to week were 9 p.m. newsmag ”Rock Center” (0.8/2 in 18-49, 3.0 million viewers overall) and 10 p.m. drama ”Law and Order: SVU” (1.7/4 in 18-49, 5.8 million viewers overall).

CW’s ”One Tree Hill” held steady (0.7/2 in 18-49, 1.4 million viewers overall) while ”Remodeled” dipped week to week (0.2/1 in 18-49, 0.5 million viewers overall) , but in good news, it really can’t dip much farther.

Preliminary 18-49 averages for the night: Fox, 6.0/16; CBS, 2.9/8; ABC, 2.8/7; Univision, 1.4/4; NBC, 1.3/3; CW, 0.5/1.

In total viewers: Fox, 18.6 million; CBS, 11.2 million; ABC, 7.9 million; NBC, 4.3 million; Univision, 3.4 million; CW, 0.9 million.