Wait. Wasn’t the whole point of creating a Carnegie Hall season for the Metropolitan Opera Orchestra so that the ensemble could explore the symphonic repertoire?

Well, that was the idea of music director James Levine, but as soon as his back was turned – or, more accurately, his shoulder was injured – Met management took the opportunity to stage an advertisement for itself in the form of an afternoon of opera highlights. Sunday’s event with Ben Heppner, Rene Pape, and Erika Sunnegardh had the feel of Three Tenors redux. Who cares that they jettisoned the Brahms First Symphony?

Someone deeply embedded in the Met publicity department is trying very hard to make soprano Ms. Sunnegardh a star. It would help immeasurably if she delivered better performances. A relative unknown, Ms. Sunnegardh was granted both the first aria and the last at this recital, but made little of such a golden opportunity.

Her first selection, “Oh smania … D’Oreste d’Aiace” from Mozart’s “Idomeneo,” was a strange choice. This is one of the toughest excerpts from Wolfgang’s notoriously misogynistic bag of tricks, the intervallic relationships between low and high notes being very difficult to navigate. Mozart requires that his woman (he made no differentiation here between soprano and mezzo) sing many high notes without any sort of run-up to them, leaving these tones naked and exposed. Difficult for the most accomplished of singers, for Ms. Sunnegardh this style was simply beyond her abilities. She was sharp in both senses of the word.

For her second-half selection, she chose more wisely, delivering a much steadier “In questa reggia” from Puccini’s “Turandot.” This was also much more of a crowd pleaser, and Ms. Sunnegardh walked away with a large ovation. But I found her voice extremely harsh throughout; even when she hit the center of a note, it was not beautiful. Further, her lyrical line needs considerable work. Until recently she was a cover artist and a good one I’m sure, but a word to the wise: Don’t believe the hype.

Those invested in directing Ms. Sunnegardh’s career might also want to prevent her from appearing on the same stage as bass Rene Pape again. As soon as this consummate artist opened his mouth to deliver a splendid “list aria” from Mozart’s “Don Giovanni,” everyone in that audience realized that this is what a great singer should sound like – bold, resonant, powerful, flexible, dexterous, commanding. Everyone else suffered severely by contrast.

Mr. Pape was also the only one of the trio to attempt, and quite successfully I might add, the creation of a character. His Leperello was wickedly amusing. For his second number, he demonstrated that even such a cavernous room as the Isaac Stern Auditorium could not hold his booming voice in the “O Patria” from Verdi’s “I Vespri Siciliani.” Magnificent.

Mr. Heppner, unfortunately, decided to partake only of two stunts. Imagine excerpting something from the end of the first act of Wagner’s “Die Walkure,” enlisting Ms. Sunnegardh for vocal and moral support, taking a dozen minutes to bring out 20 or 30 additional musicians, and then delivering only the final 2 1/2 minutes of the act, leaving off any music of substance.

This was apparently an accommodation to the struggling tenor who, truth be told, is but a shadow of his former self. The snippet was designed to show that Mr. Heppner can still hit the high A at the end – the third of the so-called “Waelse” notes – which, to be fair, he did reasonably well. However, he had to bark his way up to it and even though he nailed the pitch, the note itself was gravelly and strained.

Say what you will about the Met, but they certainly have chutzpah. In the second half, Mr. Heppner was back for the last three minutes of “Otello.” He offered no dramatic context, no lyricism, and, considering the highly emotional content of this death scene as written, not much vocal power. I love Ben Heppner, but at the moment he is undergoing a crisis that can be painful to witness.

For those keeping score, there was some orchestral music on this program. Conductor James Conlon took his charges through a very gingerly reading of Mozart’s “Linz Symphony.” This rendition exhibited signs of being but a run-through – the opening was not coordinated, for example – and ultimately was more correct than meaningful.

It would seem impossible to offer a dull version of Tchaikovsky’s “Francesca da Rimini,” the music being so lurid and febrile, but this ensemble, by never varying the rhythm and never digging below the surface, came pretty close to a sanitized and amorphous performance. Alas, no one seemed to care.