It was most fitting on the 250th anniversary of Wolfgang Amadeus Mozart’s birth that the concerts kicking off Chamber Music in Napa Valley’s 27th season last week were tributes to the Austrian genius.

And what better way to ring in a new season than with two of the world’s greatest pianists and a highly touted, Grammy Award-winning chamber orchestra.

The back-to-back concerts also marked a few firsts in wine country performances — Garrick Ohlsson and Emanuel Ax on the same stage at the same time, the first time three pianos were played simultaneously on the Napa Valley Opera House stage and, without a doubt, the first local performance of Mozart’s “Piano Concerto No. 7 in F Major for 3 Pianos and Orchestra.” On top of that, the series featured the professional debut of our very own Fritz Hatton, one of the world’s leading wine auctioneers.

After a successful series debut the previous evening, Ohlsson, Ax and Hatton teamed up with the Orpheus Chamber Orchestra Friday night for a rare performance of Mozart’s three-piano concerto.

Mozart wrote the highly enjoyable piece for his patroness, the Countess Maria Antonia Lodron and her daughters, resulting in the work often referred to as the Lodron concerto. Only 20 at the time, he composed the piece to capture the women in the most flattering light. However, Mozart was not one to conform to the demands of polite society, and the concerto ends with a joke — a false coda, followed by the real one. A few years later, Mozart did away with the third piano part in an alternate arrangement for two pianos and orchestra.

The work is much favored by famous musical families that want to show off their progeny, such as the Casadesus and Menuhin clans a generation ago. It’s amiable music, easy to play and really quite charming. A beaming Ohlsson took charge from his stage right bench, with Ax also facing the audience at stage left. Sandwiched in between, with his back to the sold-out house, was Hatton. Marked by lightness and aplomb, the 20-minute performance was delightful. Playful hand-offs and high spirits were the order of the evening, and the soloists’ refreshing naturalness won the audience’s collective heart. It was easy to tell that the musicians were having as much fun as the audience. The smile on Hatton’s face at the conclusion spoke volumes.

For an encore, the trio engaged in a bit of playful slapstick for six hands and three fannies on one piano bench.

The evening began with Ohlsson and the exceptional chamber ensemble performing the charming and intimate “Piano Concerto No. 17 in G Major.” A work that is treasured by Mozart lovers, it offers a variety of moods and never attempts to dazzle. Ohlsson gave a beautifully poised reading that was pure joy from start to finish. With the orchestra providing rich and glowing support in this mercurial work, the soloist delivered a performance that was elegant, searching and intelligent — and, honestly, magical.

The audience favorite this evening was Ax’s reading of the lovely, serene “Piano Concerto No. 25 in C Major.” The first movement is one of Mozart’s most symphonic concerto movements — a majestic military march that resulted in this work to sometimes be referred to as Mozart’s “Emperor Concerto.” This was muscular, positive playing that sparkled in the outer movements and found a natural gravity in the central Andante. Altogether Mozartean charm and the character of Ax’s playing were matched by an orchestral contribution with a strong personality of its own.

What a marvelous way to kick off the 2006/2007 chamber music season!