You hear a lot of Russian on the streets of New York these days, and there are plenty of Russians in concert halls, too. On Sunday afternoon, the Russian National Orchestra appeared in Avery Fisher Hall under the baton of Mikhail Pletnev, who is also a pianist. On Monday night, the National Philharmonic of Russia appeared in the same hall, under the baton of Vladimir Spivakov, who is also a violinist. Everything clear?

The NPR – not to be confused with our public radio — opened with one of the zippiest, rousingest pieces in all of music: Shostakovich’s Festival Overture. It begins with a fanfare, and the NPR began with a wretched entrance. The rest of the fanfare was sort of loose, too. But the fast, rousing music was fairly tight, and Mr. Spivakov arranged for some interesting dynamics.

Unfortunately, we missed that jolting, slightly wacky quality the better performances have.

Next on the program was a big concerto: Rachmaninoff’s Piano Concerto No. 2 in C minor. The soloist was Olga Kern, a Russian who won the Van Cliburn Competition in 2001. She is a striking blond woman, and she came out in bare shoulders. Anne-Sophie Mutter — the German violinist whose trademark is bare shoulders — should sue.

Ms. Kern is a brilliant pianist, with technique to burn. There is no disputing that. But there were many, many problems with this performance.

To begin with, Ms. Kern’s sound was thin and tinkly, not rich or big enough for this concerto — the Ravel G-major concerto, yes, but not Rachmaninoff’s Second. At times, that sound was brittle, too, as when Ms. Kern banged away.

Furthermore, pianist and conductor had trouble agreeing on tempo. Ms. Kern established a fine tempo at the outset, but then Mr. Spivakov slowed it down, unreasonably. Ms. Kern was like a horse champing at the bit, and Mr. Spivakov would not let her go.

In the course of this first movement, Ms. Kern indulged in some very strange rubato, some bizarre liberties. She repeatedly interrupted flow for cutesy pauses and meanderings. For example, she loved to hesitate just before a climax, or before the top of a phrase. This grew extremely tiresome. She was all too obvious in her interpreting, like a soap-opera actor laying it on thick.

And in the final notes of the first movement, pianist and conductor slowed down, absurdly.

Playing the melody in the second movement, Ms. Kern exhibited her worst tone: She plunked, coarsely. And when she played the last notes of the movement, she stared dreamily and melodramatically into space, as Liberace might.

In the third movement, slower sections were grossly mannered, and we had some more of that pausing before crestings or climaxes. And — in a kind of consistency — Ms. Kern and Mr. Spivakov slowed down for the final notes. This was maybe their 58th tempo in the last movement. All the logic that Rachmaninoff has written into his concerto, these people undid.

Ms. Kern played an encore — actually, two. The first was Rachmaninoff’s Prelude in C-sharp minor, which, in one sense, was great to hear. Pianists avoid it, because of its very popularity. But it should not have to suffer on that account. I’m afraid that the prelude suffered in Ms. Kern’s account: Like the concerto, it was mannered, toyed with, its logic — its glorious inevitability — undone. Toward the end, Ms. Kern gave a series of Brigitte Bardot pouts.

Liberace would have ralphed, and so would Rachmaninoff.

Ms. Kern then played “The Flight of the Bumblebee,” which was marvelous: fast, accurate, clear, and thrilling. There is no room for interpretation in this piece — if you can play the notes, you can’t really spoil it — and that helped immensely.

On this occasion, Olga Kern reminded me very much of Lang Lang. Neither has any problem whatsoever in playing; they can play anything, with their hands tied behind their back. The problem lies in thinking.

After intermission, Mr. Spivakov and the National Philharmonic of Russia played Rachmaninoff’s Symphonic Dances, and they did so fairly sensibly, and with tonal character. The woodwinds, for example, weren’t pretty, but they were interesting. Rachmaninoff’s waltz was not terribly together, and it could have been more ghostly, more insinuating — but it was respectable and enjoyable, like this performance at large.

Then Mr. Spivakov gave the very enthusiastic audience three encores, ending with the most popular Russian (orchestral) encore of all: the Trepak from Tchaikovsky’s “Nutcracker.” It was clean and delightsome, the best playing the NPR did all night.