From left, Joel Prieto as Ferrando, Elizabeth Futral as Fiordiligi, Renata Pokupic as Dorabella and Teddy Tahu Rhodes as Guglielmo in a dress rehearsal of “Cosi fan tutte” at the Kennedy Center. (Linda Davidson/THE WASHINGTON POST)

It can’t be a bad thing to hear an auditorium full of people laughing uproariously at a Mozart opera. And let’s hang on to the good when discussing Jonathan Miller’s production of “Cosi fan tutte,” originally created in London in 1995, which came to the Washington National Opera on Saturday night.

“Cosi” is a comedy; people are supposed to enjoy themselves, and on Saturday many of them clearly did. It’s also tricky to stage, because the plot is so patently silly: Two happy lovers are goaded by an older friend, Don Alfonso, into testing the constancy of the two sisters they adore, and learn — after pretending to be called to war, and returning in disguise to seduce each other’s partners — that all women are fickle. It’s a challenge to believe in these characters, and even more of a challenge to try, as Miller did, to bring the action into the present day.

At least, Miller said he was updating the action to the present. From the costumes (Timm Burrow revised them for this revival) and the characters’ behavior, it looked more as if he had updated it to 1980s-era Eastern Europe: some place trying a little too hard to bring across what it mistakenly believed to be the epitome of American cool, along the lines of Saturday Night Live’s “two wild and crazy guys.” The two sisters, dressed in garish ’80s colors, shimmied while they sang, like schoolteachers embarrassing their students by joining in at a school dance; the disguised men embodied creaky, decades-old stereotypes of either biker cool or rock chic.

So what was so funny? Answer: the supertitles (by Jonathan Dean, from the Seattle Opera, where this production was seen earlier). When the disguised men enter in leather jackets, long hair, and sunglasses, addressing them in ’60s-vintage slang, Despina, the sisters’ maid, says, “Where are they from? Manassas? Leesburg? Adams Morgan? Baltimore?” (The original Italian: “I don’t know if they’re Romanians [Valacchi] or Turks!”) When the two men later serenade the women, the lyrics are tweaked to echo “Lucy in the Sky With Diamonds” — again, hardly a contemporary reference, but one the opera audience certainly got.

It’s a shame that this humor wasn’t backed up by anything comparable onstage. Miller has been saying for years that his goal is to get rid of operatic cliches, so it’s frustrating to see him offer a production so rife with them, from the singers’ gestures to the outdated concepts. He violated a cardinal rule of comedy by creating characters who were parodistic; it was hard to find anything sympathetic about any of them. Furthermore, for all his lip service to naturalism, he did little to bring out the beauty of this quirky but often ravishing work. He piled on lots of stage business when the men pretended to go off to war, having them interviewed by a TV reporter. But in the ensuing trio between the two women and Don Alfonso, one of the most beautiful things in the operatic canon, he seemed at a loss to do anything at all.

And the singers were seldom able to pick up the slack. Elizabeth Futral, who sang the sister Fiordiligi, is a serious and committed singer, but prone to being distracted by cute stage business; and kneeing the would-be suitor Guglielmo (Teddy Tahu Rhodes) in the groin, or the abovementioned shimmying, got in the way of her musical focus, sometimes leading her off pitch or simply muddying her vocal lines. Rhodes himself is an imposing presence, but his large voice was woofy; and as Ferrando, the other suitor, Joel Prieto, though he had a nice taut tenor, delivered a wooden rendition of the usually gorgeous aria “Un’aura amorosa,” as if he had no idea what to do with it beyond simply producing the notes. Christine Brandes was adequate as a rather butch Despina, but Renata Pokupic’s mezzo grew colorless and strained when delivering some of the arias of the other sister, Dorabella.

Even WNO’s fine music director, Philippe Auguin, sounded out of his element, with ardent feeling but heavy tempos and a number of coordination problems between stage and pit. And the orchestra, which played so well for him in Wagner’s “Götterdämmerung,” made surprisingly uphill work of this score from the very beginning, when the overture sounded labored rather than lively.

Obviously, those who enjoyed Saturday’s performance will find this assessment unfairly cruel about an evening that gave pleasure. But there is so much more pleasure, and charm, and delight to be had from “Cosi.” A taste of all its merits came from William Shimell, who was absolutely perfect as Don Alfonso: deeply musical, vocally sound, utterly convincing onstage, and delivering exactly the kind of fresh, natural, funny performance Miller said that he wanted. His performance showed just how right this approach can be — and what a shame it was that, though it may have amused some of its hearers, it wasn’t realized better.

Cosi fan tutte continues at the Washington National Opera through March 15, with two performances by WNO’s emerging artists on March 9 and 11 and a Family Look-In for young audiences on March 10.

“Cosi fan tutte”

continues at the Kennedy Center Opera House through March 15, with performances by WNO’s emerging artists on March 9 and 11 and a Family Look-In for young audiences on March 10.