Another two-hour edition of “American Idol” carried Fox to an easy primetime ratings victory Tuesday night, but CBS held up very well with its military-set drama duo of “NCIS” and “The Unit.”

According to preliminary nationals from Nielsen, “American Idol” (13.5 rating/32 share in adults 18-49, 32.5 million viewers overall) rolled from 8 to 10, growing with each half-hour and outperforming the same night a year ago (a one-hour edition) by 17% in 18-49.

CBS was rock solid opposite “Idol,” as “NCIS” (4.4/11 in 18-49, 17.6 million viewers overall) matched its series high in 18-49, leading into another stellar perf from “The Unit” (4.9/11 in 18-49, 17.8 million viewers overall). Latter drama, starring Dennis Haysbert as the leader of a covert military team, dropped a mere 4% in 18-49 from its week-earlier premiere — despite the heightened competition in the hour from “Idol.”

“Amazing Race” was also up a bit week-to-week for CBS at 10 (4/10 in 18-49, 9.6 million viewers overall), finishing in a virtual demo draw with a repeat of NBC’s “Law & Order: Special Victims Unit” (4.1/10 in 18-49, 11.2 million viewers overall).

ABC’s new comedy “Sons & Daughters” (1.9/4 in 18-49, 5.4 million viewers overall for its hour) had a rough time opposite the “Idol” juggernaut, falling sharply from its premiere score. NBC’s competing hour of “Scrubs” (2.7/6 in 18-49, 5.6 million viewers overall) moved ahead into third place.

Top Alphabet score for the night came from 10 o’clock drama “Boston Legal” (3/8 in 18-49, 10.6 million viewers overall).

Preliminary 18-49 averages for the night: Fox, 13.5/32; CBS, 4.4/11; NBC, 2.8/7; ABC, 2.3/6; UPN, 0.9/2; WB, 0.8/2.

In total viewers: Fox, 32.5 million; CBS, 15 million; NBC, 7.4 million; ABC, 7.3 million; UPN, 2.1 million; WB, 1.9 million.