Vladimir Feltsman doesn't look flamboyant. He sits at the piano in his simple black pajama-like outfit wasting no motion. No flairs of the wrist. No tossing his head back. No anguished expressions. Just a look of bemused concentration, even while waiting patiently at the piano for the inevitable latecomers in the audience to be seated between pieces.

But what comes out of the piano is hardly standard issue. The Russian-born pianist shares an enormous gift for technique and a willful approach to the music that another famous pianist named Vladimir (Horowitz) might smile in appreciation to hear. He can rip through rapid passages as if they were child's play, pull at tempos like taffy, thunder through loud sections in a sonic blur, and all a listener can do is sit back and marvel.

Actually, Tuesday's recital of Bach and Chopin found Feltsman in a somewhat more restrained mode than usual, especially in an absolutely stunning performance of Chopin's Ballade No. 3 in A-flat major, which closed the program. Gone were any willful gestures. Instead, what emerged was Chopin of crystalline brilliance. The simple, folk-like opening paragraph seemed to rise from the piano like a morning haze, his touch producing a soft-edged sound, the pulse remaining steady. The filigree of swift, quiet runs embellished later sections like strings of pearls. Other pianists can execute them perfectly but they sound like random tinkling. His went somewhere. The big, loud phrases seem to grow organically from what preceded them.

The Bach Partitas Nos. 1 and 2, which occupied the first half of the concert, didn't start out like that. In No. 1, he became enamored of the idea of finishing almost every phrase in the opening Praeludium with a ritard, and I thought, here we go again. But the movements that followed had a rhythmic buoyancy that made them sound exactly like the stylized dances that they are. One could step lively to the Corrente, and the slow, graceful Sarabande that followed never lost its backbone.

This was not wimpy Bach. Feltsman used the pedals sparingly, creating a clarity of texture that offset a muscular approach. There was never a problem following the layers of melodic lines. He brought out the key lines beautifully without losing the essential balances of harmonic texture. This was magically so in the stately middle section of the long Sinfonia that serves as the first movement of No. 2, where the singing line of the right hand moved independently of the staccato walking bass of the left hand. The finger-crunching finale, Capriccio, couldn't have been more nimble.

Two Chopin Polonaises, Op. 26 (C-sharp minor and E-flat minor) opened the second half and had me wondering what the pianist was up to. The left hand chords seemed dense and murky and pulse seemed atypical of what one usually hears in Chopin. It was almost as if Chopin, the quintessential Polish composer, was being channeled by Rachmaninov, the Russian genius of the piano. The Polonaises' characteristic and recurring rhythmic dum-di-di-dum figures didn't seem quite crisp enough and the music seemed denser than your usual Chopin.

Feltsman seemed to find the soul of Chopin's music in the lighter, gentler phrases of the Barcarolle in F-sharp minor, which followed. The clouds dissipated, and the Ballade No. 3 brought things to a thrilling finish.

The pianist played one encore, the famous Walz in C-Sharp Minor, which he dedicated to the late Robert Harth, who brought Feltsman to the Aspen Music Festival for the first time. Harth, the longtime president of the festival who left a couple of years ago to direct Carnegie Hall, died last winter. "He was one of a kind," the pianist said. "Wherever you are, Robert, here is to you." Then he sat down and played the waltz with stunning simplicity and grace.

Monday's chamber music concert in the tent didn't start out too promising. Barber's Summer Music, a pleasant diversion from the mid 1950s, and Jacob Druckman's Come Round, an earnest, melody-phobic piece from what was left of the modernist wing in the 1990s, left me, for one, yearning for something with some stature. We got it after intermission when the American String Quartet was joined by ‘cellist Thomas Grossenbacher in Schubert's String Quintet in C major.

The doubled ‘cellos give this sunny quintet, one of Schubert's most engaging chamber works, an extra richness, making it feel almost mellow. Grossenbacher and the ASQ's own ‘cellist, Margo Tatgenhorst Drakos, kept the pulse moving in the quicker movements, but the jewel of the performance was the contemplative, serene slow movement. Time stopped, and all was right with the world for about 10 minutes.