The Mostly Mozart Festival has latched onto a successful formula: Leave them wanting more.With its program Wednesday of Dutch master Pieter Wispelwey performing just two of Bach’s six solo cello suites – amid complimentary wine at cocktail tables in Lincoln Center’s glass-walled Kaplan Penthouse – the festival presented the most tantalizing, relaxed, and qualitative concert to hit New York in recent years.

The idea, I think, was to dressdown Bach and make it part of a “special evening.” Lincoln Center called the three-part series of complete Bach suites “A Little Night Music,” which ended last night, after all, and it seems one was expected to have a little caffeine or nap beforehand because curtain time was slated for 10:30.

Performing just two of Bach’s longish multimovement works for cello – without encores or works by other composers – seemed like it would be too little to satisfy. But in practice it worked wonderfully, allowing listeners to concentrate on why these pieces dazzle, how they’re built, what drives them.

Mr. Wispelwey is a proponent of infusing into modern-style performances a smart degree of period-instrument elan.To call his musical decisions probing would be an understatement.

He began the heart-on-its-sleeve Suite No. 4 in E-flat major fluidly by emphasizing long tones topped with just a hint of vibrato at their conclusion; to accomplish this he pulled his taut bow smoothly across his gut strings, letting air gradually dilute a rich, unadorned sound. His phrasings were dotted with nanosecond hesitations, and he didn’t pound final cadential notes; he played them softly, occasionally with quick and short mordents, creating the sonic equivalent of deceptive question marks.

In the Sarabande he sang long, still intervals of open fourths, and he seemed himself to be listening to them for clues about how to move back into a propulsive rhythmic framework. Purposefully sticky double-stops astride short trill seizures distinguished the Bourees.And he sometimes even hit extra notes and strings due to casual vertical attacks in the nimble Gigue. The implied question: Why do movements like this have to be played as squeaky clean as etudes?

His approach to the opening movement of the Suite No. 2 in D minor contrasted greatly with that of many of his famous colleagues, who tend to play its compound melodic lines soupily and legato. Mr. Wispelwey’s approach – walk the harmonic skeleton of the piece by both giving each note a shortish bowstroke and keeping the rhythmic timing exact without overly emphasizing the sequences – would have been unique enough. But then he performed the intermittent runs Bach wrote to interrupt the line in tinny, neurotic fits.

To keep the middle portion of the work exciting, Mr. Wispelwey performed the aggressive Courante scratchily and brusquely. The Sarabande was a real emotional journey: Instead of squeezing the juice out of his instrument on its beefy chords, Mr.Wispelwey let his bow meander from one string to the next. Eventually he held the two notes firmly and produced a finely shaded and gradual double-stop. Finally, came a burly couple of Menuettos, and then a concluding ferociously fun Gigue whose last act couldn’t have been more symbolic of the night’s mood. By trilling the last note with its lower – not upper – neighbor tone, Mr. Wispelwey crafted a novel and surprising conclusion.

This was more than a little night music. It was among the most true, enjoyable musicmaking I’ve heard, and the most innocent,honest treat of the summer. That it happened in just one hour is a compelling reason to question the current structure of most classical music concerts. Encore.