There is a persistent rumor afoot that there is more than one Yanni (if you don’t know who that is, consider yourself fortunate).The theory goes that at least two men who look very much alike play the part so that this processor of particular sounds can appear in events all across the globe on a regular basis. If the same whisperings were about Valery Gergiev, I would be inclined to believe them. Not only does the Russian maestro lead an inordinate amount of concerts in the course of a year, even occasionally performing more than one on the same day, but there appear to be two distinct artists at work.

One Gergiev is intensely perceptive and atavistically inspirational, able to draw extremely passionate playing out of his instrumental and vocal forces and summon dazzlingly new vitality out of old scores. The other is unfocused and uninteresting, producing sloppy and wayward readings of the classics and allowing many errors of commission and imbalance in his orchestras.

But a Gergiev performance is always intriguing, especially since you never know in advance which conductor will show up. Often both faces of this Januarian creator look down upon the same audience. (For those who don’t know their Stevenson, it is only in the last pages that we discover that Dr. Jekyll and Mr. Hyde are indeed the same person.)

Due primarily to desertions fueled by economics, the Kirov Orchestra for a while resembled the population of a very small town, all of whose men went to war at the same time some years ago: The residents were either students or grizzled veterans pushing the limits of retirement. Two seasons ago, I traveled to Yerevan, Armenia, and covered opening night of the orchestra there. It had that same decimated look. The mix has now changed at the Mariinsky, but this very instability is the cause of many of its orchestra’s problems. On Monday evening, they offered a “Russia’s Greatest Hits” program as the first of three concerts at Carnegie Hall.

When Tchaikovsky went to Bayreuth in 1876 as a reporter, most of his dispatches consisted of complaints about the food, but he did return with that signature Wagnerian sound in his ear. “Francesca da Rimini” is a real bodice ripper and Mr. Gergiev delivered a highly passionate reading, not surprising considering his fine effort in “Die Walkure” at the Met this past autumn. The ensemble was focused and entrenched, but exhibited a roughness of sound that would haunt the entire evening.

Yefim Bronfman joined for the shortest and most accessible of Prokofiev’s piano concerti – the first. He began quite masterfully, playing the piece with imperial elegance. The composer himself performed it this way, more in the French style, rather than the pounding that it often takes in modern, post-Bartok interpretation. Both maestro and soloist, however, were soon guilty of hubris, speeding the tempo almost to a prestissimo. This showcased Mr. Bronfman’s ability to hit most of the notes and not die of apoplexy in the process, but left musical considerations like proper accents on the sidelines. Additionally, as several patrons who left the hall during intermission loudly pointed out, the orchestra totally drowned the keyboard in many spots.

After a bloated and murky “Capriccio espagnol,” Mr. Gergiev launched the featured work of the evening, the Ravel orchestration of Mussorgsky’s “Pictures at an Exhibition.” Here the conductor was in his element: With his short attention span, he is much more effective in an episodic piece than a sustained one. After suffering through the colorless and characterless version of the original piano score by Leif Ove Andsnes earlier this season on this same stage, it was very refreshing to hear a Russian who can imbue the individual aural vignettes with energy and dimension. Highlights included a well-drawn “Samuel Goldenberg and Schmuyle,” an unapologetically lugubrious “Polish Ox Cart,” and a “Gnomus” that showed many of the inner voices colorfully painted by Ravel but almost never brought to the surface in performance.

The best picture of all was “The Old Castle.” The alto saxophone solo was properly spectral – it had better be, since this is virtually the only part written for the instrument in the standard repertoire – but even more impressive was the background provided by the bassoon. With a relaxed embouchure and a powerful sense of tremulousness, this wind player was exceptional. I would pay real rubles to hear him in a late Tchaikovsky symphony. Much of the ensemble performance was fine, but, as with the girl with the curl, when it was bad…

Maestro Gergiev was let down three separate times by poor brass solos and completely lost control of his unhatched chicks: the winds at one tempo and the strings at another. I’m surprised their shells didn’t crack for running into each other. That grainy sound also began to grate on me, but nothing could prepare me for the shameless ending. Mr. Gergiev milked the “Great Gate of Kiev” as if he had suddenly transformed himself into Christoph Eschenbach. It takes quite a bit to offend me, but this was out and out pandering.

Part of the problem may simply be that Eastern European sound. Maybe they are crisper at home in St. Petersburg. Perhaps this was just an off-white night.

The Kirov Orchestra will perform again tonight at 8 p.m. (Carnegie Hall, 212-247-7800).