In fact, the first act of Oberto could be Verdi in any period but his last. The musical language and the dramaturgical instincts are all there. The act's finale is a bravura feat of operatic pacing: It has three climaxes, so effective that many composers would be hard-pressed to top any one of them. The only deficit is hit tunes, though in a performance as terrific as Thursday's, you might not notice.
The second act, full of bel canto formulae, sounds as if it was written first, with limpid accompanying ostinatos that become more twisted and dramatically eloquent. The ending threatens to fizzle, though AVA's music director Christofer Macatsoris - the primary hero in this feat of operatic reclamation - would never let that happen. Nor would the dramatically adept star Michelle Johnson (Leonora). When she vows to take the veil in Oberto, there's no doubt she'll be the angriest nun in the convent. Is that dramatically accurate? In such a visceral opera as this, there's only one rule: Is it effective? And it was.
Johnson displayed all the Leontyne Priceian tone of past performances, but she also sang with more meticulous accuracy. Early Verdi operas have roles requiring everything: Sopranos must have a mezzo-ish lower range and nicely floated high notes, and be card-carrying coloraturas. That last aspect has been Johnson's weak link, but on Thursday you might not have known it.
Other singers - not all of whom will be heard in the revolving casts of subsequent performances - were uniformly promising. As Cuniza (an Amneris-in-training), Margaret Mezzacappa had a good, penetrating Verdian voice, though she lacked coloristic control in her upper notes. As Riccardo, tenor Viktor Antipenko sang with a naturally plaintive quality in his opening aria but later lacked a firm sense of vocal line.
In the title role, baritone Scott Conner navigated everything with confidence and style; he is a few years away from having the vocal weight for vengeance-declaring moments so essential to Verdi baritones.
Macatsoris could have galvanized the performance with merely fast tempos. However, he seemed to trust the opera, despite its nonreputation. Its music truly lived up to what some Verdians describe as the fierce noonday sun of the composer's creative life.
2 p.m. Saturday at the Grand Opera House in Wilmington and 7:30 p.m. Tuesday at Centennial Hall at the Haverford School. Information: 215-735-1685 or www.avaopera.org or, for the Wilmington performance, 302-652-5577 or www.ticketsatthegrand.org.
Contact music critic David Patrick Stearns at firstname.lastname@example.org.