It was a full moon Thursday night, the perfect touch for the ghostly doings of "Giselle." Yet American Ballet Theatre's performance of the ballet at Wolf Trap couldn't have been more bland.

In the full glare of afternoon sunlight yesterday, a matinee performance of the same ballet saw sparks flying on the stage. So much for atmosphere.

The difference between these performances, the second and third of the five "Giselles" ABT is staging here this week, illuminates what it is about this ballet that continues to provide a challenge to contemporary dancers.

Thursday's performance was devoid of passion between Marianna Tcherkassky as Giselle and Ross Stretton as Albrecht. Stretton was so utterly deferential a cavalier and so introverted in his Act 2 melancholia that it was difficult to accept him as the instigator of these dramatic events. While his technique was more than adequate, his interpretation was a fade-into-the-scenery cipher. Tcherkassky's Giselle, too, was weaker than in her opening performance of the role on Wednesday.

What was of interest on Thursday was Nora Kimball, who, dancing Myrta, marked her ABT debut. And a spectacular debut it was. Formerly with the Stuttgart Ballet, Kimball has a presence at once lyric and gossamer, yet of pliant power. Her Myrta was regal rather than demonic, conveying a marvelous hauteur and elegiac mystery.

By contrast, yesterday's matinee belonged to the principals. Cynthia Harvey's Giselle, Robert La Fosse's Albrecht and Victor Barbee's Hilarion were all of commanding presence.

Harvey's Giselle was sure and inspired, filled with illuminating detail. In recent seasons there has been a deepening lushness as well as emotional maturity to Harvey's dancing, and this Giselle confirmed her powers.

Her mad scene was nothing short of extraordinary. This was not prettified distress, but bizarre, out-of-kilter abandon. With her head working with the idiot mechanism of a doll's and her body held in distorted poses, her inner pain was made horrifyingly graphic.

La Fosse's was not a great Albrecht, but certainly a fiery and impetuous one, notable for the consistency of his interpretation and the detail of his mime. There was no sense of his simply "filling" musical time, as have the two previous Albrechts. Rather, he inserted bits of business that provided information about the emotional state of his character as well as improved the dramatic sense.

Invigorating what is all too often a throwaway role, Victor Barbee also proved electrifying as a sympathetic Hilarion.

Not that the daytime performance was without its problems. "Giselle" is the quintessential moonlight ballet, and Act 2 suffered when its lighting effects could not be discerned in the full daylight. This problem provided some sense of what a radical departure it was in theatrical staging when in the Romantic Era, ballets were staged for the first time with the house lights down.