The two big Thursday rivals this season, Fox’s American Idol and CBS’ The Big Bang Theory (5.5/16), both inched up last night. But Idol (5.7/6) went up more to break the shows’ tie over the past two weeks and claim the top spot for the night in 18-49 outright. Big Bang still won the head-to-head contest from 8-8:30 PM (5.5 vs. 5.2). With the resolution of the Wednesday night cliffhanger (the girl that fell of the stage was OK, got a “yes” too), Idol was up 6% from last Thursday’s fast national, and Big Bang was up a tenth. Fox’s The Finder (2.3/6) slipped a tenth from last week. Fox (4.0/11, 12.2 million) won the night in 18-49, CBS (3.6/10, 14.3 million) in total viewers. CBS’ Rob (3.4/9) was up a tenth from last week, Person Of Interest (3.3/8, 15.1 million) matched its series high from last Thursday, and The Mentalist (2.9/8, 14.4 million) was flat in 18-49 and posted a season high in total viewers.

I’m not sure NBC should’ve used “Voice encore hits a nine-week high for NBC in Thursday 10 PM hour” as a headline of its ratings alert this morning. It speaks more to the lousy ratings the network’s regular fare has delivered in the time slot this season, especially when you factor in that the rerun of the post-Super Bowl Voice fetched a modest 1.5/4 in the demo. Earlier in the night, 30 Rock continued its wild week-to-week ratings swings — down double-digits one week than up by that much the next. After a 19% drop last Thursday, an hourlong episode of the TV industry comedy (1.6/4) was up 23%. The Office (2.5/6) was down 11% to a season low and the lowest demo rating since its low-rated freshman midseason run in 2005. Up All Night (1.8/4) was flat.

ABC’s Wipeout (1.5/4) was down 17% from last week for a season low. Grey’s Anatomy (3.9/10) was up 11% from its fast national last Thursday (like Idol and Big Bang, the medical drama is almost always adjusted up a tenth in the finals.) Private Practice (2.3/6) was flat. The CW’s The Vampire Diaries (1.2/3 in 18-49, 1.2/4 in 18-34, 3 million) was even in 18-49, up 20% in 18-34 and up 11% in total viewers. The Secret Circle (0.8/2 in 18-49, 0.7/2 in 18-34, 1.8 million) was up 14% in 18-49, 17% in 18-34 and 6% in viewers.