NYTimes.com: They said teen pop wouldn't last. But not only did it last, it also evolved. On Wednesday night, Justin Timberlake (of *NSYNC), the golden boy of teen pop, and Christina Aguilera, its black sheep, began their 45-date Justified and Stripped Tour at the America West Arena here. But before going any further, here are some quick answers to the pressing questions fans and pop-obsessives have been asking about the tour: yes, Mr Timberlake played *NSYNC songs too. No, the two didn't sing together. Yes, Mr Timberlake held his own as a solo act. No, the audience was not full of squealing preteens. And yes, Mr Timberlake was the headliner. Oh, and the T-shirts were $35. Though the teen pop tag lingers, both singers are now 22. When sontemporary teen pop emerged in the late '90s, it was led by former Mouseketeers crooning slow-churning, high-saccharine ballads pledging everlasting love for the girls and submissive devotion for the boys. But now that the class of 1992 (the year Ms Aguilera, Mr Timberlake, Britney Spears and JC Chasez of *NSYNC were all on 'The All-New Mickey Mouse Club') has matured, its graduates have shed their mouse ears, reached college age and discovered what life away from home can be like. Thus, teen pop has entered its independent 20-something phase, with its stars breaking away from their handlers, managers and career advisers. Some pundits see this musical self-determination as career suicide because neither Ms Aguilera nor Mr Timberlake's most recent albums sold as well as their previous work. But others see it as canny image manipulation to survive in changing times. After all, their fans are also discovering the liberation that Ms Aguilera and Mr Timberlake proudly flaunt... Mr Timberlake may not be the best singer; on his own his voice can come off as too high and pinched. But using the same basic stage set as Ms Aguilera did, he put on a phenomenal show. Unlike Ms Aguilera, when he updated his older material -- *NSYNC songs like 'Gone' and 'Girlfriend' -- it worked, chiefly because he performed the songs as if he were still proud of them. Also unlike Ms Aguilera, who hardly moved in comparison, his moves -- resembling Bob Fosse doing Michael Jackson -- nearly put his backup dancers to shame, particularly when he clambered on top of a piano to show off some with Prince-like polish. Backed by a 14-piece, horn-infused live band, the minimal beats created by Timbaland and the Neptunes for his solo deut, 'Justified', turned into bombastic jams. But the most impressive jam was unexpected, when Mr Timberlake hovered over the audience in a cherry-picker playing human beatbox and battling the drummer and a DJ on rap and club classics like 'Planet Rock' and 'It Takes Two'. If Mr Timberlake's gift in *NSYNC was his harmonies, it became clear at his first American concert here that his gift as a solo artist is his intuitive sense of rhythm.

AZCentral.com: Reinvented pop superstars Justin Timberlake and Christina Aguilera launched their 45-city 'Justified and Stripped Tour' in Phoenix on Wednesday, and their new, more mature images and music received a strong thumbs-up from the near-sellout crowd. In staging the only huge pop tour of the summer, the pair of former bubblegum singers showed off their newest albums, which lean toward R&B, rap and, in Aguilera's case, some rock. However, Timberlake moved even more toward stripped-down, old-school soul in his 80-minute set, which kept the America West Arena crowd on its feet most of the time... Timberlake's set started out looking like an *NSYNC flashback, with the singer and his eight dancers moving crisply through the kind of dance moved made popular by his on-hiatus band. However, his performance of songs from his 'Justified' album made it clear that Timberlake's heart lies in the soul music of his native Memphis, Tenn. While the CD has a hip-hop overtone, hits such as 'Rock Your Body', 'Like I Love You' and 'Last Night' received a more sleek, soulful sound at the hands of Timberlake and his large band, which included three horn players, a DJ and two keyboardists. Two *NSYNC songs, 'Gone' and 'Girlfriend', also got retro treatment. He took a break from the tight choreography during slower tunes such as the bittersweet 'Cry Me A River', which built to an amazing climax with the help of his four talented backup singers, and 'Still On My Brain'. Timberlake made several subtle costume changes and employed some fireworks and some well-time pyrotechnics, but his music remained the focal point. It was good to see Timberlake tone down the Michael Jackson nods from his CD, but a dance routine on top of a grand piano inspired by the Gloved One was phenomenal.

ContraCostaTimes.com: It was pretty much the same ol' world of teen pop arena concerts: screaming, bad fashion, more screaming. Showcasing the healthiest careers left of the late '90s music explosion, Justin Timberlake and Christina Aguilera pulled into the Oakland Arena Friday night to re-enforce some simple truths. The level of importance probably depends on age and point of view, but nevertheless, here's the breakdown: Timberlake doesn't sing nearly as well as Aguilera, and Aguilera doesn't dance nearly as well as Timberlake. But since Timberlake doesn't look like Cher dressed as Lilly Munster, he's not quite as interesting as Aguilera. However, 20,000 girls scream louder for Timberlake, who just isn't quite as fun without his four pals from *NSYNC. Not that anyone noticed amid the noise-worship. What does all this mean? Very little, other than the tidal wave that was 'TRL' teen pop has subsided to where two of its biggest acts now tour together for maximum exposure... As far as the singing went, Timberlake had to work harder -- not that the mostly female hysterical crowd even cared. His thin voice makes his charm extremely important, which was obvious during the light ballad, 'Still On My Brain'. With *NSYNC, vocal deficiencies could be masked with harmonies and all-out movement. But even with dancers and back-up vocalists, Timberlake's show was a far cry from the spectacle of his boy band days. But charm and celebrity go a long way with a crowd, where all a guy has to do is ask, "Is there anybody out there who wants to be my girlfriend?" and he gets buried by screams. Timberlake moved agilely through his record 'Justified', with a few hitches and even fewer memorable moments. He didn't pick up much momentum until the Britney Spears-inspired 'Cry Me A River', after which he climbed up a crane to swing out over his legions. Standing 30 feet overhead, Timberlake turned loose on some human beat box into the mic, parrying with the real scratching coming from DJ Furious. It was all made so much better by one of the greatest rock drummers to ever climb behind a kit, Fish from Fishbone. His typical chops don't match Timberlake's style, but nevertheless emerged ocasionally in refreshing staccato bursts. The synchro dancing was tight, the band was good, and Timberlake smiled his way through it all. To expect more would be asking for disappointment. It was that simple.