Finnish violinist Pekka Kuusisto is a longtime friend of American composer Nico Muhly, and their collaboration was cemented Friday evening at the Ordway in the St. Paul Chamber Orchestra's U.S. premiere of Muhly's new violin concerto.

Entitled "Shrink," the piece is for stringed instruments only and received a taut, incisive performance from the SPCO players.

Kuusisto's solo part bobbed and wove its way amid the pulsing textures of Muhly's opening movement, one moment interweaving with the accompaniment, the next cutting free with jagged motifs and angular lunges toward the top end of the instrument.

Rhythm continued to play a bigger part than melody in the calmer middle movement, although Kuusisto's extended duo with concertmaster Kyu-Young Kim had the intricacy of needlepoint tapestry and a keening fragility.

The finale — "short, nervous and scattered," as Muhly describes it — returned to an obsessive focus on driving rhythmic patterns and sharp, staccato writing in the solo part.

Kuusisto nailed its technical challenges, but for all the hyperactivity and bustle, the effect was impassive.

The second U.S. premiere of the evening — "Paradisfåglar II" by Swedish composer Andrea Tarrodi — plowed a very different type of furrow in a version for full orchestra of a piece written for strings 12 years ago.

The eight-minute work was inspired by a BBC Planet Earth film about birds of paradise, and Tarrodi mimicked their billing and cooing in a slew of layered string glissandos, with twittering responses in the woodwind instruments.

Much of the piece had an airborne, hovering quality achieved by light articulation and an impressionistic approach to texture.

That quality of suspended animation was evocatively conjured by the SPCO players and made one hungry to hear more of Tarrodi's music.

Flanking the premieres were two starkly contrasting slices of Mozart.

The evening opened with six of his brief, pithy Contredanses, music intended to provide pleasant background ambience at social occasions.

Kuusisto led a gracefully pointed account of the dances from first violin and was in the concertmaster's chair again for the performance of Mozart's 40th Symphony, which concluded the concert.

The minor-key 40th is frequently labeled a tragic symphony, one of Mozart's darkest and most intense creations.

Kuusisto and the SPCO players challenged that assumption in an interpretation in which more light intruded than usual, and the mix of moods was teasingly ambivalent.

That was particularly true of the slow movement, taken by Kuusisto at a quicker pace than usual, emphasizing its elegant dance rhythms and suggesting an element of spry comedy in the interchanges between the violin and woodwind sections.

The outer movements were grave in tone but never overdramatized, revealing intimate details of Mozart's orchestration that are engulfed in more tempestuous performances.

The results were consistently absorbing and often thrilling, too — the brilliantly executed double-bass runs of David Sheets and David Grossman in the finale were just one example of many high-class moments in an outstandingly involving interpretation.

Terry Blain is a freelance classical music critic for the Star Tribune. Reach him at artsblain@gmail.com.