Unless a ballet company has a choreographer ensconced, it must borrow works from other contemporary or past repertories. Unless ballets are danced by those who created them, it will be said that the current dancers don't understand the style -- or some version of "it ain't what it used to be."

American Ballet Theatre has one of the most borrowed repertories around, and it took several gambles last night on the second program of its three-week Opera House season. It danced Merce Cunningham's "Duets" (and can ballet companies do modern dance?); perhaps more daringly, it presented a new cast in Twyla Tharp's "The Little Ballet," a work tailor-made for Baryshnikov.

A tautly constructed series of duets for six couples, each with a specific identifying movement motif, danced to the gently percussive metronome tappings of John Cage's "Improvisations III," "Duets" should have provided a welcome, astringent contrast to a program otherwise danced to the music of Minkus, Glazunov and Glazunov. Unfortunately, last night's cast was bland to the point of anonymity -- only Nancy Raffa and John Turjoman had the necessary edge -- and the entire proceedings were disappointingly limp.

Tharp's "The Little Ballet" hasn't been around long enough to be indelibly associated with Baryshnikov, but he was central to the idea of the ballet. Basically an extended pas de deux for a man and a young girl, with three other young women as a sort of backup group, the work seemed to portray Baryshnikov, the company director, and his new young charges in a very unequal partnership. The long, beautifully composed solos were danced with the fluid, masculine grace that is Baryshnikov's style. Impossibly difficult, the dancing seemed impossibly easy.

Robert La Fosse took on the Baryshnikov role last night and Cynthia Harvey was cast opposite him for the pas de deux, turning the central relationship upside down; a naive boy and a sophisticated woman. Given these circumstances, Harvey could do little but seem unattainable, a bit like a muse, and dance like hell, which she did, her clean, classical style showing off the kinks and quirks of Tharp's choreography like jewels on a black dress.

La Fosse, with the more difficult task, made it succeed on his own terms. He was a classical soft-shoe dancer, at times moonstruck, at times fatuously happy, somehow making the choreography suit his lanky body and Broadway style.

The rest of the program -- divertissements from two 19th century Petipa classics -- would only have been daring in ABT's infancy; the idea of Americans dancing Russian classics has caught on since 1940. Cynthia Gregory and Fernando Bujones danced the first performance of the season of "Paquita," which has been given a new, uncredited backdrop. Impeccable dancers, they gave impeccable performances, Gregory's in particular enlivened by the same wit and dash that made her opening night "Raymonda" so glorious.

In last night's "Raymonda," Magali Messac turned out a playful, relaxed and mature performance that made this pieced-together collection of excerpts seem like the whole ballet. Without taking the tiniest liberty or being the least coy, Messac flirted with both her partner (Kevin McKenzie) and the choreography, her dancing warm, womanly and resplendent.