Fox is still in the hunt at the halfway point of the May sweep after dominating Wednesday with “American Idol.”

Although NBC built an early lead for the month with big two-part earthquake movie “10.5” and the finale of “Friends,” Fox remains in position to challenge for the adults 18-49 crown on the back of its hot music talent show.

“Idol,” which comprises nearly 20% of Fox’s sked this sweep, was at it again Wednesday: An expanded 66-minute seg that eliminated the contestant field from four to three was easily the night’s No. 1 program in both adults 18-49 (10.0 rating/24 share) and total viewers (22.28 million).

It teamed with a winning perf at 8 for a 44-minute episode of “That ’70s Show” (5.8/18 in 18-49, 11.53 million) to give Fox the night in all key categories. Nestled between ” ’70s” and “Idol,” a 10-minute trailer for upcoming 20th Century Fox theatrical “The Day After Tomorrow” drew 14.94 million viewers.

With seven hours of “Idol” ahead in the next two weeks, including a two-hour finale on the sweep’s final night, Fox has a chance to make things interesting down the stretch. Through Wednesday, NBC led in 18-49 with a 5.3 rating/15 share, with CBS still in second (4.0/11) and Fox close behind in third (3.9/11).

NBC leads in adults 25-54 (6.0/15) and appears headed for victory there. It’s also the midpoint leader in total viewers (13.3 million), although CBS (13.1 million) is expected to prevail for the month.

Elsewhere Wednesday, two hours of “The Bachelor” produced ABC’s strongest perf on the night in 10 weeks.

After spec “The Bachelor: The Women Tell All” was a solid but distant second to “Idol” at 9 (4.2/10 in 18-49, 9.28m), the regular “Bachelor” seg airing this week at 10 (6.0/15 in 18-49, 12.45m) won in 18-49 over tough competish that included NBC’s “Law & Order” (5.6/14 in 18-49, 15.86m) and CBS spec “Carol Burnett Show: Let’s Bump Up the Lights” (3.5/9 in 18-49, 13.61m).

“Burnett” drew a respectable aud but it was a far cry from the 30 million who turned out for a clips spec based on the variety show in November 2001.

NBC didn’t do much with its 8 o’clock Wednesday psychic spec “The Mentalist” (2.2/6 in 18-49, 6.19m).

At the WB, “Smallville” (2.1/6 in 18-49, 4.54m) ran second at 8 in men 18-34 (2.9/10) and “Angel” (2.2/5 in 18-49, 4.02m), one week from its series finale, again built on its lead-in in several demos.