Fox’s "American Idol" sank to another historic low Thursday night, while ABC rolled to a win on the continuing strength of two drama series. Meanwhile, CBS’s coverage of the "March Madness" NCAA Men’s Basketball Tournament got off to a soft start, based on Nielsen overnights for the key 18-49 demo.

TVbytheNumbers.com reports that the first night of the NCAA hoops tourney delivered a preliminary 1.1 average in viewers 18-49 for CBS — off a hefty 31% from the equivalent number a year ago. But the report notes that significant adjustments can be expected when the final numbers come in, due to the nature of live sports programming.

Fox saw the numbers for "American Idol" continue to erode, as the singing competition fell 14% from a week ago to a 1.9 average in 18-49 — the lowest number in history for the series. Fox’s "Hell’s Kitchen" was also down, losing 15% from the season premiere to a 1.7.

ABC continued to get good numbers out of "Scandal" and "Grey’s Anatomy." "Scandal" was the top broadcast show of the night with a 2.9 average in the 18-49 demo, up 4% from last week, while "Grey’s" also ticked up 4%, registering a 2.4.

The soft spot in ABC’s Thursday lineup continues to be "Once Upon a Time in Wonderland," which equaled the series low it set last week, a 0.8 average in 18-49.

NBC, which tied CBS and Univision for third place overall among the broadcast nets, filled one hour of prime with a repeat of "Hollywood Game Night" (0.9 average in 18-49), while the rest of its lineup ticked along in the 1.1 to 1.2 range. "Parenthood" equaled the 1.2 average it pulled in last week; "Parks and Recreation" also equaled its own 1.2; and "Community" bounced back from its series low, rising 10% to a 1.1.

For prime time overall, ABC won the 18-49 demo with a 2.0 average, followed by Fox (1.8 average) and then the pack: Univision, CBS and NBC, all with 1.1 averages. Fox snuck ahead in total viewers, averaging 6.83 million to edge ABC (6.80 million), both well ahead of CBS (3.8 million), NBC (3.5 million) and Univision (2.7 million).