Christina Aguilera's Oakland, California, stop on her Back to Basics tour was anything but simple. Featuring numerous sets, costume changes for nearly every song, and drastic revisions of her earlier hits, much of the ninety-minute show emphasized the twenty-six-year-old's evolution from bubblegum starlet to "dirrty" vixen to her current incarnation as retro-styled soul siren. Opening with "Ain't No Other Man" as Aguilera and her eight dancers made their entrance down a lit staircase in sharp white suits, the presentation was a marked improvement over her 2003 Justified & Stripped tour with Justin Timberlake. Now moving more confidently with classier choreography, more enthusiastic dancers, and a tighter band, Aguilera demonstrated that her once-uncertain stage presence has nearly caught up with her famed vocal dexterity.

Aguilera's not one to hold back. Just as she'd rather embellish a melody than sing it simply, her show emphasized extremes -- short skirts with long trains that she nervously pushed away from her high stiletto heels, heartfelt proclamations of respect to soul singers "Back in the Day," lace chaps that her dancers attached to her legs to prove that -- despite her marriage -- she's "Still Dirrty." As she sang "Oh Mother" in praise of her mom divorcing her allegedly abusive father, staged footage flashed behind her of a man repeatedly punching a woman as blood dripped from her face. Just as Tina Turner proclaimed in "Proud Mary" that she never does anything "nice and easy," Aguilera proved once again that she never does anything nice and subtle.

When her material suits her full-throttle attack, Aguilera triumphs. Staged as revival meeting, "Makes Me Wanna Pray" celebrated flesh and spirit with gospel fervor as dancers spun around Aguilera while she dropped to her knees, James Brown-style. For the Beatle-esque "Welcome," the staging took a circus motif as dancers swung on trapezes and breathed fire. "Beautiful" remains such a perfect, self-empowering ballad that no amount of excess notes can defeat it, and "Fighter" ended the show on a hard-rocking high. Aguilera made no mention of the fact that her Oakland gig with supporting acts the Pusycat Dolls and Danity Kane fell on International Women's Day. Whereas Madonna pioneered her brand of bustier feminism with knowing finesse, Aguilera and pals opt for strip-club bombast, even when belting pro-female anthems. Now more woman than girl, Aguilera's looking and sounding stronger than ever, but could benefit from a little adult nuance.