Latonia Moore Steps In to "Aida" at the Metropolitan Opera As often happens with cover singers at the Metropolitan Opera the soprano Latonia Moore had less than a day's notice to take over a major part, in her case the title role of Verdi's "Aida" on Saturday afternoon. Violeta Urmana, scheduled to sing, was ill. Sondra Radvanovsky had filled in for her on Tuesday. So with just some studio coaching sessions and no rehearsal onstage, Ms. Moore, a 33-year-old Houston native, made her Met debut in the last performance of the revival of the company's 1988 production this season, with Marco Armiliato conducting. The audience loved her. When Ms. Moore took her solo curtain call at the end, she received an ecstatic ovation. Cory Weaver/Metropolitan Opera Latonia Moore as Aida in her Metropolitan Opera debut. She brought experience to bear, having sung Aida last season at Covent Garden in London and the Hamburg State Opera. On Saturday her voice was radiant, plush and sizable at its best, with gleaming top notes that broke through the chorus and orchestra during the crowd scenes. She also has appealing stage presence, and brought palpable emotion to her portrayal of the tormented Aida, an Ethiopian princess held captive in Egypt, torn between love of her homeland and passion for Radamès, the leader of the Egyptian forces. That Ms. Moore is a young black artist singing the most famous African heroine in opera lent an extra dimension to her affecting portrayal. Ms. Moore has enormous potential. Yet her singing was far from flawless. Midrange phrases, especially at softer volumes, tended to turn patchy and tremulous. Now and then her pitch lacked focus. She may have some technical issues to work out. Still, this was a notable debut of a richly talented singer. That even major artists have vocal imperfections was demonstrated by Marcello Giordani's performance as Radamès. His big top notes rang out excitingly. But his lower range was sometimes weak and leathery. And he resorted to falsetto singing, it seemed, in high pianissimo phrases. On the other hand, the force-of-nature mezzo-soprano Stephanie Blythe, as Amneris, was as amazing as ever. In the end this was Ms. Moore's day. Bouquets were tossed, cheers rang out, and she looked overcome with excitement.