When a young soprano decides to end her professional debut recital with Leonore's stentorian "Pace, pace, mio Dio" from Verdi's "La Forza del Destino" and it turns out to be the finest performance of a splendid program, you know you have come upon a significant voice. That's what happened with Washington soprano Alessandra Marc at the Kennedy Center's Terrace Theater last night.

She lashed into the great Verdi aria with a superbly controlled crescendo and decrescendo on the opening syllable, and then descended that octave to the second syllable precisely on the note. The whole aria was full of intensity and power.

Marc has been around for a while, mostly as a soloist in choral works, but last night was her big test. She came out of it sounding as if she is first and foremost an opera singer. The voice is really big, especially at the top. It is also quite accurate; I can't recall anything that was flat or sharp all evening. Last night it also had little vibrato, which is fine for some music. But it could stand some more color elsewhere, as in "Depuis le jour" from Charpentier's "Louise."

Marc was a little weaker in the art songs, but still impressive, especially in the four Brahms lieder. Her "Zueigung" by Strauss was outstanding, full of power.

"Dich teure Halle" was especially exciting. "Ebben, n'e andro lontano," the second encore, from Catalani's "La Wally," was a little square. The first encore, an aria from Lehar's "Paganini," was a joy, full of style.

Marc's is a marvelous voice. Who knows where it is going?