LOS ANGELES — "American Idol" crowned its first real rocker Wednesday as David Cook rolled over 17-year-old balladeer David Archuleta to become Idol No. 7.

The win for Cook, 25, a bartender from Blue Springs, Mo., came as somewhat of a surprise, considering Tuesday's performances and the judges' reactions, which swung almost unanimously in Archuleta's favor.

"I started this season, much to Simon's chagrin, as the 'word nerd' — and I am absolutely at a loss for words now," Cook said.

The two-hour-plus finale show, in which the winner was announced at the 1:59 mark, paraded out not only this season's eliminated contestants but also present and past pros. ZZ Top traded "Sharp Dressed Man" licks with Cook, and OneRepublic dueted with Archuleta on "Apologize."

The double-David duel was a study in contrasts. Archuleta was one of the many pageant kids who have made up a significant portion of "Idol's" rosters, entering contests at age 10 and singing on "Star Search" at 12.

Musically, Archuleta fit the conservative, ballad-heavy mode "Idol" judges and producers seem to favor, rarely venturing into uptempo realms.

Cook, on the other hand, said he came to the Omaha auditions to provide moral support for his brother Andrew; talked into singing, he was passed through to the Hollywood rounds while his brother wasn't. (That's not to say Cook is an amateur: He has sung in several bands and released an independent solo album, "Analog Heart," in 2006.)

He became one of the first contestants to play electric guitar onstage and made a specialty of applying rock textures to softer songs such as Lionel Richie's "Hello." His penchant for dramatic rearrangements marked him as a mold-breaking contestant.

The juxtaposition of the Davids represents the "old," safe "Idol" sensibility against an edgier breed of contestant, a contrast thrown into dramatic prominence when, for Tuesday's last song, Cook chose a medium-sized mid-'90s hit from Collective Soul that the audience had never heard him sing, while Archuleta reprised his signature song, John Lennon's "Imagine."