Terrence McNally’s passion for Maria Callas is getting a serious workout in Washington this month, and not just in Master Class, the one McNally play in which the 20th century’s greatest singer—OK, whatever, its most polarizing—actually appears. The Lisbon Traviata details an opera queen’s delirious pursuit of an elusive Callas bootleg; in Golden Age, the newest and untidiest of the three McNallys at the Kennedy Center, a 19th-century composer goes all weak-kneed over a singer whose interpretive gifts and vocal flaws were very like those that would, a century later, drive the warring Callas factions to such heights of rhetoric. (In fact, it’s a Callas recording standing in for the voice of that singer in one crucial Golden moment.) What Master Class offers is a satisfying release for all the pent-up desire embedded in the other two plays—and it gets right to it, as Tyne Daly’s imperious Callas comes striding out of the wings, looking around for “the first victim” in an afternoon that’s meant to be devoted to the sharing of musical wisdom. The real master classes (at Juilliard circa 1972, and available in a magnificent CD set) did stick to the pedagogical agenda, but in McNally’s invented version, La Divina spends as much time reflecting on her dramatic triumphs and domestic tragedies—and taking tasty little digs at her rivals—as she does telling the assembled audience that “this is a classroom—this is not about me.” By turns touching and maudlin, entertaining and indulgent, McNally’s homage doesn’t hold up quite as well in Stephen Wadsworth’s handsome staging as the original production does in memory, but then it lacks the energizingly nervy phenomenon that was Audra McDonald’s combative, live-wire Sharon. (The third of Callas’ student sacrifices, all brio and bad attitude, she marches onstage to declare that she’ll be singing Lady Macbeth’s punishing letter scene—and then, to everyone’s astonishment, she sings the bejesus out of it.) Laquita Mitchell makes a suitably pugnacious Sharon, if not quite a catalyzing one; other issues are the casting for the part of a handsome, empty-headed tenor (Ta’u Pupu’a, honey-voiced but so wooden you can see his grain from the balcony) and the odd, disorienting discovery that Master Class and Lisbon Traviata are structurally an awful lot alike, with their comic show-off-your-opera-chops first acts and their post-intermission focus on tragic divas bristling at the younger models who’ve arrived to replace them. It’s that last bit that goes begging here: Without a fearsomely gifted, fiercely temperamental Sharon to underscore the finality of her eclipse, Daly’s Callas is left with not much more than the familiar stories and the unexpected jokes. Unlike Lisbon Traviata, this play gives the former sufficient room to breathe, and with the effortlessly wry Daly handling the latter with aplomb—plus Jeremy Cohen’s gamely professional accompanist at the keyboard and Alexandra Silber’s sweetly scattered, endearingly flustered Sophie to liven up the first act—it makes a respectable cap for the “Nights at the Opera” repertory, if not quite a rousing one.