Susanna Mälkki, the latest in a series of excellent conductors sent round the world by the Finnish nation, directed Thursday’s Boston Symphony concert, which surrounded a newly composed work of outstanding brilliance with French warhorses.

When one thinks of the term “toccata” (touched), one remembers Baroque harpsichord music and 19^th-century French organists, and moto perpetuo pieces like the Sinfonia from Bach’s Cantata BWV 29, “Wir danken dir, Gott, wir danken dir.” Dieter Ammann subtitled his new Piano Concerto “Gran Toccata,” an apt designation for a single movement that is both pianistically and orchestrally motoric in the grand manner for most of its 30 minutes, and mostly grandly loud as well.  Strikingly, during this half-hour challenge, interest never flagged. Often the massive texture submerged the soloist nolo contendere (concertare in Latin means “to struggle,” after all) in a diffuse, overwhelming, but unified welter of sound. The piano played relentlessly in feverish virtuosity; the orchestra kept just as furiously busy. The total sound rarely allowed a dialogue of forces; rather it synthesized piano and orchestra into one huge instrument. And yet, the composer convincingly organized the ebb and flow of ideas into temporally and dynamically contrasting episodes, including two substantial solo cadenzas for the piano where an expressive, even Romantic, sensitivity appeared. Amman wrote the concerto for last’ night’s intrepid and eager soloist, Andreas Haefliger.

The composer made his wry sense of humor manifest from the very first bar, when the concerto began with a fortissimo A, a single pitch the piano hammered several times, barely a minute after the orchestra had tuned up to the same note. Then other instruments took up the A quickly with different figures and short snatches, spreading it through a multiply divisi string section, with wild col legno, Bartók snaps, and behind-the-bridge bowing, and then the whole ensemble began to articulate with frantically complex textures regulated by huge tutti downbeats. Among these outbursts were regular and sustained appearances of triadic or seventh-chord harmony in a paratonal environment — chords that are clearly derived from ordinary tonality but that have no tonal relationship to their context. In this regard Ammann can be considered a disciple of Alban Berg’s harmonic sense — where a familiar harmony, without any tonal context, is chosen for its sheer sound. But we heard several episodes of frank tonality, complex harmony to be sure, but with perceptible organization into phrases. Sometimes there was a prominent F-sharp major — D-sharp minor mixed pentatonicism; in a quiet section near the end, divided strings crept slowly upward, chromatically and by quarter-tones. Midway through there appeared a regular pulse on one note or one chord, almost like a stuck CD. A penultimate section in chorale-like brass octaves made the concerto sound like an act of solemnity;  a scream of desperation for high trumpets interrupted. The final measures focused on a plain repeated French-sixth chord, pianissimo, for the solo piano, fading out with a soft roll on the bass drum.

The orchestra calls for woodwinds by threes, normal brass, and an enlarged percussion section (four players) like that of Varèse’s Amériques that was constantly occupied — one striking section included chimes, marimba, and vibraphone all going like mad together, not punctuating but reinforcing the pianism. The program notes mention that the composer “spent several months researching types of piano texture that appealed to him.” Some of these inspirations were obvious: the piano cadenza in Tableau II of Petrushka appeared at least twice; the martellato style of the third movement of Ravel’s concerto was a sometime component; the first solo cadenza came across like a Chopin nocturne as Prokofiev might have reimagined it, while the second, stormier cadenza could have had Prokofiev’s own Toccata for a background. Ammann also seems to have admired the double-note right-hand sound that emerges in Chopin’s and Saint-Saëns’s concertos. Ammann’s background in jazz is less obvious, but if one can imagine a big-band sound amplified registrally and even explosively, one can get a sense of the density of his orchestra. In all, it was refreshing to hear a new piano concerto conceived as such a brazen and even strident continuity, in which tonal, paratonal, and atonal styles blend so colorfully together, and without even a hint of octaves in the piano. The composer shared in the prolonged cheers, and he seemed satisfied.

The evening began with a quiet reading of Fauré’s beloved Pavane, in which Elizabeth Rowe (flute) and Robert Sheena (English horn), played superbly warm solos. The pizzicato accompaniment, however, proved generally too quiet for effective tone to carry. Mälkki announced the second section, beginning on a loud octave D,  with a big downbeat gesture — bigger than necessary, even though the composer wrote ff.

Olivier Messiaen’s early l’Ascension (1935), has been criticized as incorporating a debased hyper-pietistic aesthetic that verges on kitsch, but the separate “symphonic meditation” from it, “Alleluia on the trumpet, alleluia on the cymbal,” didn’t seem that way; it’s rather a lively rhythmic exercise in orchestral splendor. Mälkki’s precise and responsive beat telegraphed the varied and often complex and incisive rhythms, seemingly varying between fast 2/16, 3/16, and 6/16. An epigraph, according to the handout, comes from Psalm 47, but I thought first of all of Psalm 150, the musician’s psalm, incorporating praise of God with trumpet, cymbal, and “everything that hath breath.”

A solid traversal of Debussy’s La mer closed the concert. Once again, though,the loudest places sounded too loud, despite Debussy’s markings. The last page of De l’aube à midi sur la mer, for instance, goes to fff only once, and Debussy’s normal ff shouldn’t be like Stravinsky’s, or Mahler’s for that matter. The long melody in p octaves for four muted horns at m. 35, expressif et soutenu, should really be softer still. Additional problems came from the tempi, especially in Jeux de vagues, where metronome markings are insufficient, and where a basic tempo is necessary for the entire movement; much of this movement felt rushed, to fortify the energy at climaxes; thus, at the end of the movement Mälkki overcompensated by being way too slow. I’ve remarked elsewhere about the considerable orchestral problems of balance and articulation in La mer, and these often remain even in first-rate performances. Yet this vigorous performance featured wonderful orchestral playing, well communicated by the conductor. (One could see a hardbound copy of Marie Rolf’s edition of the score in the Debussy Œuvres complètes on the music stand.) And yes, Mälkki thankfully included the generally omitted horn-trumpet fanfares at mm. 237-244 of Dialogue du vent et de la mer.

Mälkki conducts in a clear and precise, and often athletic style. Her strong downbeats particularly supported the constant agitations of Ammann’s unfamiliar new concerto. At other times she could have restrained her beat; smoother results might have come from more economical arm motion and from less left-hand mirroring. Some of the too-loud accents may have resulted from too-forceful time-beating. Nevertheless, I sensed promising auguries that Mälkki and the Boston Symphony will prosper together.

Mark DeVoto, musicologist and composer, is an expert in Alban Berg, also Ravel and Debussy. A graduate of Harvard College (1961) and Princeton (PhD, 1967), he has published extensively on these composers and many music subjects, most notably, harmony.