Vladimir Ashkenazy closed out the National Symphony Orchestra’s subscription season with a bracing trio of classics by Walton and Shostakovich. This repertoire plays to the NSO’s strengths and avoids its weaknesses, and the performances are well worth hearing.

The principal offering, Shostakovich’s epic Tenth, is one of the great symphonies of the past century. Composed in a period of relative liberation, immediately after the death of Stalin, it looks back on the sclerotic oppression of his era with grim, clear honesty. It is also the first of several works that uses a motto (D, E-flat, C, B) that “spells out” the composer’s name.

Free of the need to send coded cries for help or subversive taunts toward the regime, the symphony eschews the banality that can be found in its predecessors. It is by turns elegiac, furious and puckish, but the overall impression is one of granitic mastery.

Ashkenazy, one of the world’s greatest pianists for many decades, has also forged a solid conducting career, including long associations with the Philharmonia and Cleveland orchestras. His gold-plated musicianship is evident, but so is his lack of formal training in the craft. For the audience, he’s fun to watch, like a kid suddenly let loose in a toy store, clenching fists in delight, jerking and twisting impishly. In Walton’s virtuoso “Portsmouth Point” Overture, he made the tricky rhythms sting, at times reminding some of Pee-wee Herman.

The orchestra is likely less enamored, although Ashkenazy’s angular style imparts tension where it needn’t be. In the long paragraphs of the Shostakovich, the phrases didn’t build organically; there was too much focus on character and passing detail. Ashkenazy’s beat patterns with his baton (upon which every orchestra relies) were haphazard, and the NSO players often looked and sounded tense.

That isn’t automatically a liability in Shostakovich, of course. His idiom requires stamina, concentration and sometimes brute force, but little else that falls under the heading of “style.” Although the music itself is full of ambiguity, he doesn’t call for a lot of subtlety — in different bow-strokes, for example. The NSO is well versed in his music, although it hasn’t played this symphony in 17 years. The piece fits well because it relies heavily on the low strings, which are very strong in this orchestra. There were also particularly outstanding solos from the principal oboe and bassoon, and that newfangled contraption that the contrabassoonist now plays produced tones of stentorian grandeur.

The evening’s soloist, cellist Steven Isserlis, delivered an affecting, richly shaded rendition of the Walton Concerto. He is a deft, idiomatic player of great accuracy, but sometimes the physical presentation — wonderfully dramatic tossing of his Bernadette Peters curls — had to substitute for volume. I once heard Zara Nelsova play the same piece on the same instrument Isserlis now uses (a glorious Stradivarius), and the thing roared.

Isserlis, by contrast, is notorious for his refusal to press or force his sound. But in concertos with large orchestras, that integrity costs. In the middle register, especially, the instrument seemed to melt into the orchestra, with many wonderful passages lost. But in the finale’s two cadenzas, Isserlis was able to showcase a full range of colors without worrying about projection, and the virtuosity and highly dramatic presentation were memorable indeed.

This program repeats Friday and Saturday night.