Fast National ratings for Tuesday, May 19, 2009.

The season's final performance episode of "American Idol" did typically strong ratings for FOX, but the special sneak preview of "Glee" squandered most of that audience, allowing ABC to win the night overall.

Among adults 18-49, FOX won the night with a 6.3 rating, followed by the 4.0 rating for ABC and CBS' 3.2 rating. NBC was a distant fourth in the key demographic with a 1.5 rating, beating the 0.9 rating for The CW.

Overall, things were a bit more complicated. FOX averaged an estimated 16.91 million viewers in primetime to top the 15.99 million for ABC, but ABC's 10.1 rating/16 share beat the 9.7/15 for FOX. Isn't Nielsen strange? Anyway, CBS was third with a 9.3/15. NBC's 3.0/5 and the 1.3/2 for The CW trailed.

FOX grabbed the 8 p.m. hour with a 13.2/21 for "American Idol," better than the 10.1/17 for CBS' "NCIS." A "Dancing with the Stars" recap and an NBC "Most Outrageous Moments" special were third and fourth, beating the 1.2/2 for The CW's "Reaper."

ABC won the 9 p.m. hour with the 11.7/18 for the start of the "Dancing with the Stars" finale. CBS' "The Mentalist" was second. FOX's "Glee" took third with a 6.2/9 and finished second in the 18-49 demo, which looks good until you note that it lost nearly half of its lead-in immediately and shed nearly four million viewers half-hour to half-hour. FOX will now have to hope there isn't additional attrition, with "Glee" going back on the shelf until fall. NBC's "Law & Order: Special Victims Unit" repeat was fourth, bettering the 1.5/2 for the season finale of "90210."

"Dancing with the Stars" closed with a 13.5/22 for ABC. CBS' "Without a Trace" was second with a 7.4/12, leaving a "Law & Order: Special Victims Unit" repeat in third for NBC.

All ratings information comes from preliminary Fast National Nielsen data, which includes live and same-day DVR viewing. All numbers are subject to change.