The New York City Opera's production of "Tosca" last night at Wolf Trap reached its stride in Act 2. This is where it has to happen in "Tosca" if it is to happen at all. And in this production, a competent but routine Act 1 led to an intense, grimly satisfying Act 2.

"Tosca's" second act is strong stuff: sex, violence, an impressive array of sadomasochistic overtones and a splendid turnabout when the victim becomes the aggressor and Tosca plunges a carving knife into the villain Scarpia, screaming "Ecco il bacio di Tosca" ("This is Tosca's kiss").

It may be overdrawn and melodramatic, but there is nothing else in opera quite like it -- and last night it was done with an energy, a precision and an attention to fine detail that lifted the production suddenly to a new status.

In Act 1, Elizabeth Holleque had been a generic soprano, cute and coy with a pretty little voice that did her bidding precisely while she flitted from flirtation to jealousy. In Act 2, in a head-on confrontation with Julian Patrick's strong Scarpia, she began to sound a bit like Maria Callas -- vibrant, intense and tightly controlled in her dramatic nuances, though considerably sweeter and more agile of voice in her climactic aria, "Vissi d'arte," which received the best singing of the evening. A few minutes later, her "Muori, dannato" ("Die, damn you") had an intensity almost on the Callas level.

She was easily the star of the show, though her tenor partner Robert Grayson made a fine recovery after a rocky start. His "Recondita armonia" and, to a lesser degree, all his singing in Act 1 sounded rather forced. Then in Act 2 all he had to do was get through an interrogation with torture. This seemed to do his voice good -- in Act 3, it was clear and ringing in tone and used with grace and agility.

Joseph McKee made much of the minor role of the sacristan in Act 1, developing all kinds of business that not only kept the staging from becoming static but also formed a consistent and believable characterization. Some of this effect may be credited to the expert stage direction of Frank Corsaro, but McKee is clearly a fine singing actor with an excellent voice.

Corsaro contributed some telling details -- in Act 3, for example, the silent disposal of the corpse of a torture victim over the wall of the Castel Sant'Angelo during an orchestral interlude, and Spoletta kicking the corpse of Cavaradossi to show his frustration as the final curtain descends. But generally, Corsaro concentrated simply on telling the story, with considerable clarity.

Alessandro Siciliani conducted a vigorous, expressive interpretation, with an orchestra perceptibly richer and more disciplined than we are accustomed to hearing in opera here. "Tosca" will be repeated tomorrow night