Chookasian's debut performance was a resounding success and a recording of that performance was given to conductor Thomas Schippers by McGuire at the Festival of Two Worlds the following summer. McGuire recalls, "He was astonished by Lili's voice, but he had nothing in mind for her at the time." However, two years later Schippers wanted "that extraordinary Adalgisa from Arkansas" for a concert performance of Prokofiev's "Alexander Nevsky" with the New York Philharmonic. However, he could not remember her name and was unable to track her down until a chance meeting with Sheldon Soffer tipped him off that she was working with the Baltimore Opera Company under Rosa Ponselle. Chookasian had spent the last year studying under Ponselle and had created her second opera role on stage with the company, Azucena in Verdi's "Il trovatore" in 1960. Schippers contacted Chookasian to come up for an audition, and after hearing her, she was immediately engaged to sing the music of Amelfa Timoferevna (in "Alexander Nevsky") for her New York Philharmonic debut in early 1961.