Waltz king Johann Strauss did not write his comic masterpiece "Die Fledermaus" (The Bat) as a New Year's Eve piece, but its effervescent spirit and infectious melodies have given it that status ever since the Vienna State Opera initiated its annual New Year's gala productions in which famous performers -- often theater people or retired opera singers -- are introduced to perform light music during the second-act party scene.

Thursday evening, Opera Theater of Pittsburgh initiated its own version at the Byham Theater. Though not quite New Year's Eve, it's the right season, and the company hopes to make its English-language production a local tradition. Toward this end, OTP artistic director Jonathan Eaton has interpolated Pittsburgh references and brought in a local Gypsy Strings Orchestra and two couples from the Duquesne University Tamburitzans, as well as the deservedly popular Lenora Nemetz, a Pittsburgh native who went on to become a Broadway star.

The local additions are provincial and mostly superfluous, but the lively production is a delightful treat that is well worth continuing. Certainly the enthusiasm of Thursday's first-night audience seemed never to flag during the three-hour performance.

The farcical plot of "Fledermaus" centers on the revenge of Dr. Falke on his aristocratic friend, Eisenstein, who once humiliated Falke after a masked ball in which he came dressed as a bat. With the help of the super-rich Prince Orlofsky, Falke creates a party in which Eisenstein, his wife, Rosalinda, and her chambermaid, Adele, are embarrassed for their foibles, lies and infidelities. All this on a night that Eisenstein is supposed to report to jail for having kicked a tax collector.

Eaton has staged the work deliciously, amid colorful sets by Stephanie Mayer-Staley that do not always make sense but add to the zany atmosphere. Eisenstein's drawing room, for example, is dominated by a giant picture frame, through which the characters must walk in and out, occasionally tripping in the process.

Eaton's best work is in individual scenes and small ensembles. The first-act trio, in which each character alternates between truth and dissimilation, is hilarious. He is less effective in the crowd scenes, where the chorus tends toward the chaotic. And the Tamburitzans are placed behind the gypsy band, where their dancing is frequently hidden.

Although "Fledermaus" is technically an operatta, with spoken dialogue between numbers (in the manner of a Broadway musical), Strauss' score is sophisticated and operatic, calling for technical virtuosity and interpretive acumen from all the principal singers. And, for the most part, the singing here is quite good.

Most spectacular is the agile coloratura and alluring stage presence of Diba Alvi, as the pert and sexy chambermaid Adele. She was predictably impressive in the popular Laughing Song, then later topped that by stealing the show with a brilliant rendition of the less familiar Audition aria in Act 3.

Soprano Laura Knoop Very, who has done admirable work with this company in the past, was miscast as Rosalinda von Eisenstein. Vocally, the part lies too low for her, and many important extended passages were inaudible. While her high notes were penetrating, they were also sharp and shrill. Worse, she lacked the style for this elegant lady. Frumpy in the first act, she was unable to deliver the great Czardas -- the work's central solo scene -- with the dash and charisma it demands.

On the other hand, there was world-class vocalism from tenor Raymond Very, this Rosalinda's onstage and offstage husband. In every line, his voice trumpeted through the others with true operatic power. Tenor Daniel Snyder, who appeared in OTP's small version of Wagner's "Ring," has less pure sound to offer than Very but he was marvelous in impersonating Rosalinda's pompous former lover, who seduces her with his singing, and sailed through bits of the tenor repertory with great aplomb. Craig Verm's tenorish baritone sound was less impressive, but he made much of Falke's stage business.

Then there were the two comedians -- very funny women playing male roles -- "in travesty," as they used to say. Myrna Paris sang Prince Orlofsky's music an octave lower, in male register! She is always a dominating stage presence, although the role's musical demands did not well accommodate her deep contralto. Nemetz, who gave her own rendition of "All the Jazz" in the ballroom scene, substituted for an ill Kevin Glavin in the slapstick jailer's scene that opens Act 3, combining comic skills with athletic acrobatics in a uniquely personal way.