Donizetti's "L'Elisir d'Amore" is one of opera's loveliest romps. It is packed with charming melodies that singers and audiences love, in a story that is simplicity itself. The whole thing revolves around a poor bashful kid who, thanks to a quack doctor's bottled elixir -- pure Bordeaux wine -- wins the pretty, rich landowner, taking her away from the handsome sergeant.

The Washington Opera is betting its wad on the popularity of a new production of this piece, performing it 11 times this month in the Kennedy Center's Terrace Theater. Last night's opening had lots to like.

With attractive sets by Zack Brown, who also provided lovely costumes, the score runs along nicely under Cal Stewart Kellogg's enlivening direction. It is also helped by Lou Galterio's sensible direction. Sensibility matters because in as lightheaded a work as this many directors tend to overdo everything: the comedy, the buffo aspects, the local-yokelry. Galterio encourages everyone to behave like human beings with normal sensibilities. His payoff is a comedy of credible situations.

Rich Adina is understandably piqued when poor Nemorino, who she might have supposed would jump through her hoop, suddenly becomes suspiciously indifferent. Fortified by Dr. Dulcamara's potent elixir, Nemorino is horrified when Adina agrees to marry Sergeant Belcore before the elixir has time to work. It all looks and sounds reasonable. Don't worry -- everything comes out right at the end.

The singing is well done all around. Gimi Beni's Dulcamara has every bit of know-how to make the quack doctor persuasive. Every gesture, the patter in rapid-fire recitatives and ensembles, and his obvious authority give his singing and acting just the right stamp. From his entrance to his final departure, he is a model. The staging of the doctor's scenes is imaginatively enhanced by the work of mime Art Treichel, who is in charge of the tricky paraphernalia.

As the young lovers Marianna Christos and Tonio Di Paolo -- both American singers -- won some enthusiastic applause. Christos is striking in appearance and vocal style. Her voice has a cutting edge but also lovely lights and shadows which she uses with skill. There is brilliance at the top. With all that at her command, Christos must work for more nuance and still greater accuracy on every note, some of which was missing.

Di Paolo has a lovely voice, exactly the kind for Nemorino. But he tends to use it at the full more than the great singers in the part have done, and he frequently drives it just above the pitch. His "Una furtiva lagrima," the one familiar aria in the opera, won him a big hand. But he can and should do it better.

Allan Glassman's Belcore, solidly sung, was a bit vindictive in manner, and rather one-dimensional. Judith Borden, in the important role of Giannetta, contributed fine singing and acting.

As in the previous night's "Rake's Progress," the chorus was superb. They are grand artists, marvelously trained by William Huckaby. Kellogg and the orchestra got along well but there are some obvious weaknesses in the playing.