It’s true that Madelon’s scene is almost surefire; I’ve seldom seen it fail. But I have also never seen it have quite this effect, achieved with a voice that now consists of several notes in authoritative chest at the bottom, then a thinned-out pitch or two, then some reasonably gathered tone to the upper G, where this contralto cameo tops out. So while there was more voice than I expected at this stage of the journey, voice was not the secret ingredient here. Nor am I a big believer in the often-ascribed quality of “charisma,” though it was obvious from the Rosina of a half-century back (and from the fact that I remembered it, took note of it) that a free, open stage personality was at play. I’m a believer, instead, in knowing what you’re doing, and I think that Elena Zilio sharpened her good stage instincts, her awareness of her appeal, on the wheel of the actor’s craft. She knew how to fill herself with the terrible circumstances of Madelon’s crucial life moment, to bring them onstage with her and to hold them at bay till her mission of yielding her grandson as child-soldier to the Revolution was accomplished. That, I believe, accounts for the riveting quality of those few minutes, that extra sense of presence we were all caught up in.

There is not much point in reviving Thaïs without two principals who can catch and hold us in  that same way, and for more than Madelon’s moment. I am fond of the piece, but it is from Massenet’s second drawer, not the top one that holds Manon and Werther. It is the casting of the title role that has been held responsible for its stretches of success (none very recent) since its premiere in 1894, and it’s no doubt the prospect of courtesan allure transformed into religious ecstasy, as embodied by some unusual feminine specimen, that has sold most of the tickets whenever Thaïs was on the bill. But the other major role, that of the fanatically ascetic Athanaël, is no mere foil. It’s his agony of confused passion that impels the story. The opera’s delicious swap of sex and salvation can’t  work without extraordinary couple chemistry.

The present production, with direction and design by John Cox, was devised nine years back for Renée Fleming, who looked glamorous, sang prettily, and seemed to enjoy herself in a not-quite-extreme-enough way. Her Athanaël was Thomas Hampson, offering his customary combination of stylistic finish, welterweight baritone tone, and intelligent interpretive choices, much too restrainedly realized. This season, the Thaïs was Ailyn Peréz. Quiz: what functional deficiency, common in many contemporary female voices, restricts the presence and color of  her predominantly attractive singing in important phrases at or near the bottom of the staff in her long solo scene at the start of Act II, or at other similar spots throughout the score? Right. Unlike many other soprano instruments similarly limited, though, Peréz’s takes on some core as it ascends. She can draw a firm line, inflect it and shape it. Her range extends to the indicated high Ds without thinning, though also without that extra release that makes the phrases soar. She sang some beautiful pages, and I’d be happy to hear her again in more supportive surroundings (see below).