It's a rare occasion when a musician's feet are the subject of so much chatter, discussion and admiration.

When organ doyen Paul Jacobs approached the Létourneau Pipe monster — 143 stops, 8,356 pipes — he unbuttoned his formal jacket, draped it atop the wooden frame of the instrument, put on his studious spectacles and made a last minute decision to forgo the partiture for his River Oaks Chamber Orchestra debut performing Félix-Alexandre Guilmant's Symphony No. 1 for Organ and Orchestra from memory.

Jacobs had performed the solo sonata version of the opus numerous times, yet this was his first time taking on the concerto with full accompaniment.

The Saturday evening musicale, titled "Musical Melange and Organ Solo," at the Church of St. John the Divine also programmed music of Haydn and Shepherd School of Music's Pierre Jalbert, under the direction of conductor Edwin Outwater.

ROCO founder and principal oboist Alecia Lawyer's coaxes her team of minstrels to take risks, not to leave anything unaccounted for on the written page. So stunts like this, adventures that append a level of excitement that don't transfer onto recordings, are as expected as the many notes on a staff.

The possibility that things can take a turn for the worse titillate the senses into paying even closer attention to the tuneful action.

For Jacobs, this wasn't akin to when he persevered through an 18-hour musical of marathon of Bach's complete organ opera, or when he executed multiple nine-hour, all-Messiaen recitals in an eight-city tour.

At 35 years old, Jacobs is pure musical exhibitionism — with class. On the organ.

From the opening colossal, angular, rhythmically dotted ballyhoo fanfare, Jacobs flaunted that which renders him a leading artist in his generation: A sensitivity for exquisite articulation, seamless phrasing and an affect that propels listeners to listen forward, as if Jacobs hypnotizes audiences to predict his next move.

Like a perfectly framed couplet in a Shakespearean sonnet.

But like a man whose music is brimming with shock and awe, Jacobs sets up fans to be not always right. Those unexpected, poetic twists and turns are what draws concert goers into his world of rich imagery and narrative — and keeps them there, at the tip of his fingers and happy feet.

Jacobs' colorist intuition suffused the second movement Pastorale with sounds — from clean, supple purity in the high register to delicate pastel rumblings in the low tessitura — that offered a mystique that slipped away from the hedges of the physical confines of the church. Off to the countryside, of bucolic beauty with sylphs and shepherds, faintly revived by genteel triple meter lilting melodies and countermelodies — where motion and stillness stumble upon their balance — suitable for the aesthetic of turn-of-the-century Paris.

Nostalgic double reed fragments and a rising flute commentary looked onto a soaring empyrean region, only to be awakened by the verbose and roaring third movement, the Allegro Assai. For those sitting close enough to watch Jacobs feet, the fugue-like contrapuntal writing put his tootsies through a gracefully-choreographed musical ballet fluttering swiftly between heels and toes.

It's not often that Bach is chosen for an encore, albeit to satisfy the appetite of the members of the Houston Chapter of the American Guild of Organists, who sponsored Jacobs' visit, and considering his instrument, his moment in the spotlight couldn't have ended any other way that with the great A minor Fugue, BWV 543.

Guest maestro Edwin Outwater, music director of the Kitchener-Waterloo Symphony in Ontario, Canada, collaborated synergistically with the energetic soloist and impassioned ensemble. In this second appearance with ROCO — I imagine there will be a third — he addressed the curious concert goers with comfortable ease, as if he were having an exchange over a hearty bottle red wine.

Opening the concert was ROCO's surprise selection, Gustav Mahler's Blumine, which was intended to be the second movement of his Symphony No. 1 in D Major. The former's title alludes to a floral spring spirit, mused after romantic German novelist Joseph Victor von Scheffel's Der Trompeter von Säkkingen (The Trumpeter of Säkkingen).

 Joseph Damian Foley, who's principal trumpet of the Rhode Island Philharmonic and who's on the faculties of the New England Conservatory and The Boston Conservatory, presented a profound melody over a murmuring tremolo in the strings. His sound's treatment of the large intervalic leaps and honest harmonic progressions extended — as Mahler's music should do — a sensitive, absolute world in a single phrase, one which resurfaced through the seven-minute Andante allegretto.

When crafting Autumn Rhapsody for string orchestra, Jalbert imagined the shades of warm tones that awash the American Northeast, and their transformation from fall to winter. While the second violins suspended a trembling pedal tone, others enchanted with a collection of pitches that forge satisfying open sonorities and serene dissonances, a nod to the music of Aaron Copland, particular the introduction to his Appalachian Spring.

Principal cellist Shino Hayashi united those pitches to tender an alluring, singing air that captured the essence of fleeting, transitional moments like autumn. At times, Jalbert opted for a pointillistic technique, where the theme was distributed note by note in different instruments.

A whimsical, bright and clever interpretation of Haydn's Symphony No. 82 in C Major "The Bear" evinced the composer's genius at fusing light Classicism, fresh melodic ideas and earthy harmonies.

That left listeners smiling, and wanting more — on their feet.