NBC’s foray into the kitchen, “Celebrity Cooking Showdown,” proved to be hard for auds to digest in its premiere Monday.

Weeklong event, which matches top chefs with some familiar actors and athletes in a culinary competition, flamed out on its opening night — and then had to face Fox’s “American Idol” Tuesday. Also Monday, ABC underwhelmed the competish with the series preem of “What About Brian.”

According to Nielsen, “Celebrity Cooking Showdown” opened at 9 o’clock to a fourth-place 2.8 rating/7 share in adults 18-49 and 8.18 million viewers overall — down 20% in the demo vs. what “The Apprentice 5” earned in the hour a week ago.

Result was especially disappointing since NBC again dominated the preceding hour with gamer “Deal or No Deal” (4.5/13 in 18-49, 15.32m).

As it did Tuesday, “Cooking Showdown” will air at 8 o’clock through Friday. NBC was hoping to strike again with a scheduling format that worked well in December for the launch of “Deal or No Deal.”

At ABC, “What About Brian” (3.2/8 in 18-49, 7.13m) ran third at 10 behind a repeat “CSI: Miami” on CBS (5.1/13, 16.33m) and a firstrun “Medium” on NBC (3.9/10, 10.76m).

“Brian,” an ensemble romantic drama that had a special preview airing Sunday after “Desperate Housewives,” was on a par with what limited series “Miracle Workers” scored in the 10 o’clock hour recently for ABC. “Brian” slipped a bit from its “Supernanny” lead-in (3.7/9, 8.99m).

Fox took the night in 18-49 with a slot-leading “24” at 9 o’clock (5.5/14, 13.26m) and the second-place “Prison Break” at 8 (3.5/10, 8.18m).

At CBS, a firstrun “The New Adventures of Old Christine” (3.7/9 in 18-49, 11.38m) virtually matched the numbers of its repeat lead-in “Two and a Half Men” (3.7/9, 11.93m).