The season nine closer of American Idol predictably came out on top during May sweeps and delivered its most-watched finale since 2006 on CTV, though numbers were down stateside for U.S. caster Fox.

Canadian viewers jumped on the Idol bandwagon to the tune of 3.3 million viewers for the splashy two-hour finale on May 26 that featured performances from stars including Christina Aguilera, Alice Cooper, Janet Jackson and Joe Cocker. (All numbers 2+ and based on PPM data).

The show peaked at 4.8 million viewers at 10:03 p.m. as Illinois-native Lee DeWyze was crowned the winner. While CTV enjoyed an increase for the Idol finale versus last year’s 2.6 million viewers (with the help of the Personal People Meters), the numbers on Fox were down 18% from 2009, according to USA Today, as Idol continues to lose steam on the whole.

Ratings for the show may further be impacted next year with the departure of brash but popular judge Simon Cowell.

CTV also saw solid numbers for the season ender of Dancing with the Stars, which drew two million viewers for the final performance episode on May 24, outpacing the series finale of Global’s 24 with 1.3 million viewers. Dancing was followed by the season enders of Two and a Half Men, The Big Bang Theory, and CSI: Miami, each with 2.3 million viewers on CTV.

Meanwhile, Global’s NCIS finished its seventh season with 2.1 million viewers on May 25 — opposite the performance ep of Idol on CTV — while The Good Wife ended its rookie season with 1.3 million viewers, facing tough competition from the results ep of Dancing with 2.5 million viewers.

As CTV and Global get set to unveil their fall primetime schedules this week, each offered a different outlook of the 2009-10 season on Tuesday, with Global trumpeting its wins in the 18-49 demographic.

The broadcaster says its primetime audience is up 29% in the demo versus last season on the strength of Survivor, House and newcomer Glee.

CTV painted a different picture of the season, noting that its schedule delivered seven of the Top Ten programs in Canada in the 2+ and 18-49 demographics through May 30. The broadcaster declared Grey’s Anatomy the top drama of the season with an average 2.8 million viewers, though its top-rated reality Idol landed slightly behind Global’s Survivor for the year.