CBS, which earlier this week renewed about two-thirds of its sked for next season, may have another hour it can count on after “The Unit” opened impressively Tuesday.

Fox easily led the night with hefty scores from “American Idol” and “House,” but Tuesday’s biggest story was the Eye drama about a covert military team, which posted the second-best demo delivery — as well as the largest overall audience — for any drama bow this season.

Also Tuesday, ABC did OK with the premiere of off-kilter comedy “Sons & Daughters,” but NBC may wish it had kept “Joey” in Hiatusville after the second-year laffer opened weakly on its new night.

According to national estimates from Nielsen, “The Unit” averaged a hearty 5.1 rating/12 share in adults 18-49 — the best showing for a noncrime CBS drama since “Touched by an Angel” six years ago — and 18.5 million viewers overall, the largest audience for a regular Eye program in the timeslot in nearly seven years.

The drama from 20th Century Fox Television, starring Dennis Haysbert and Scott Foley, improved on its solid lead-in from “NCIS” (3.8/10, 17.21m) and also gained 1 share from its first half-hour to its second (4.8/12 to 5.3/13 in 18-49) — a good sign for a premiere.

The 5.1 rating in 18-49 reps a 50% rise from the 3.4 CBS had averaged in the 9 p.m. hour since “American Idol” bowed on Fox in mid-January and shook up the night. Among all regular-slot drama bows this season, only ABC’s “Invasion” (which followed “Lost”) had a higher 18-49 score.

“The Unit” also earned a big 7.0/15 in adults 25-54, drawing nearly the same rating among men as women.

CBS ranked second from 8 to 10, as “American Idol” (11.8/31, 28.56 million viewers overall) and “House” (8.4/20, 20.56m) both remained in control of their hours. Despite the strong drama competish from “The Unit,” “House” had its second-best showing to date.

At ABC, “Sons & Daughters” opened at 9 with a third-place 3.5/8 in 18-49 and 8.41 million viewers overall — the net’s best regular-show demo perf there in four months — before dropping off some at 9:30 with its second episode (3.0/7, 7.50m).

For the hour, the 3.25 average in 18-49 marks a 27% improvement over the 2.55 rating ABC had averaged in the hour since “Idol” debuted.

These aren’t great numbers, but for several reasons — ABC’s fragile state of comedy, the good reviews the show got and the fact that single-camera comedies typically take a while to catch on — the Alphabet figures to be patient with “Sons.”

Both “Sons & Daughters,” which comes from NBC Universal Television, and “The Unit” will have “American Idol” as competish the next two weeks, as the elastic music competition expands to two-hour segs.

Also Tuesday, NBC’s “Joey” returned on a new night after a nearly three-month rest and laid an egg (1.4/4 in 18-49, 4.09m), while CBS’ “The Amazing Race 9” won in key demos at 10 (3.8/10, 9.46m) but is still off vs. ratings for recent editions.