Backstreet Boys didn't get to "Everybody (Backstreet's Back)" until halfway into their Saturday night show at MCI Center, but by then everybody--particularly the screaming, screeching, predominantly adolescent girls who make up their core fan base--had rendered that statement superfluous. After all, it wasn't just the weekend shows at MCI that sold out instantly--Backstreet Boys' entire "Millennium" tour accomplished that feat in 39 cities simultaneously less than an hour after tickets went on sale. They're back, indeed.

The tour, named after the Boys' second stateside release, also 1999's bestselling album, dispensed with potential pre-millennial tensions by serving up two hours of the infectious dance pop and sweet ballads that have made Backstreet Boys the biggest pop phenom since, well, 'N Sync.

The show, played out on a sci-fi-inspired set, kicked off with an entrance worthy of the Jackson 5 as the airborne (and securely harnessed) Boys snowboarded over the audience to the in-the-round (technically, pentagonal) stage. This offered everyone in the full house an essentially unobstructed view, though the Boys had to play to different sections of the crowd as the night wore on. That task was made somewhat easier by huge video screens that bore their beaming visages even when parts of the audience had to make do with the Backside Boys. Not that anyone was complaining, mind you.

The opening portion of the concert featured infectiously bouncy dance-pop hits such as "Larger Than Life" (and louder, too) and "Get Down," as well as jubilant up-tempo ballads such as "(I'll Be) the One," "As Long as You Love Me" and "Don't Want to Lose You." The confused romantic subtext that informs most of the Backstreet repertoire--and endears them to their young fans--was evident in the two songs that followed, the group's breakthrough hit, "Quit Playing Games (With My Heart)" and the petulant "Don't Want You Back." For the first, the Boys--Nick Carter, A.J. McLean, Brian Littrell, Howie Dorough and Kevin Richardson--slipped back into their harnesses for more aerial excursions over the audience--pretty fly for five white guys.

Sometimes, the stage got overly crowded, particularly when the Boys were accompanied by dancers on such flashy production numbers as "Larger Than Life," "Everybody" and "It's Gotta Be You," the first encore number; unfortunately, as the last devolved into a completely unnecessary cutting contest between the dancers and an overlong introduction to the band, it diminished the climactic energy of the show.

Backstreet Boys features three lead singers--Carter, Littrell and McLean--though all five members took their turns at the microphone. McLean is probably the strongest of the three. However, the squeals that accompanied each and every band member's video close-up and shaky solo performance suggested a loyal but not particularly critical audience. The group did better on the harmony front, particularly on a sweetly sentimental "The Perfect Fan," Littrell's ode to his mother and her unconditional love and support.

Though the uptempo material was bright and sassy, fans also got a heavy dose of romantic musings via the lush "Spanish Eyes," the neo-doo-wop "I'll Never Break Your Heart," the wounded "Back to Your Heart," and, particularly touching to the full house of aching hearts, "No One Else Comes Close" and "All I Have to Give." The last was performed in hilariously garish zoot suits and straw hats. Over the course of the concert, Backstreet Boys actually managed more costume changes than Cher did in her recent appearance.

The MCI shows were only the second stop on the "Millennium" tour (opening dates in Florida were Floyded out) and there were some minor technical glitches. The Boys still need to work the room more efficiently--always a challenge when performing in the round--and they could space out their audience greetings rather than bunching them up at the beginning. Otherwise, they likely pleased a lot of attending parents (a k a designated drivers) who long for wholesome pop in a culture where such a notion sometimes appears antiquated. But, as Backstreet Boys sang in their closing number, "I Want It That Way." So did their fans.