Over the past few years new life has been breathed into that most Baroque of instruments the harpsichord by a young generation of players, and leading the charge has been the exciting Iranian-American keyboard maestro Mahan Esfahani.

His discs – eight of them to date, live and studio, on various labels including Hyperion and more recently Deutsche Grammophon – have been picking up gongs and five-star reviews worldwide. What’s more, he has broken plenty of new ground, including being the first harpsichordist to feature in the London Proms – something the great homegrown talents George Malcolm and Trevor Pinnock never managed.

So it was with enormous anticipation that the discerning and devoted regulars of the Utzon Music Series at Sydney Opera House awaited his debut appearance. And they weren’t to be disappointed.

From the moment he sat down at the beautiful Sydney-made Carey Beebe instrument, composing himself momentarily before launching into the portentous opening bars of JS Bach’s Toccata in C minor BWV911, listeners knew they were in for a special treat.

Of course there’s the seamless fingering, miraculous light touch and faultless articulation and intonation, but those are qualities that many keyboardists possess. What sets Esfahani apart is an innate feeling for the humanity of the music, the personality behind the notes, which is something we associate more with the Classical and Romantic repertoire, and certainly not with the cerebral approach many performers take when it comes to Bach.

Take, for example, the Andante of the Italian Concerto (a welcome change of programme from the original selection of pieces from the Well-Tempered Clavier).

This is one of those heavenly melodic solos that abound in Bach’s works, more often for voice, violin or oboe, and in this instance over a repetitive six-note bass figure. Esfahani gave the two repeated final notes such a variety of timings – here slightly rushed, there lingering and delayed – that the feel behind the lovely melody in the right hand was one of wistful hesitancy.

It set up the Presto finale beautifully, this being taken at breathless speed with a suspicion of Baroque barrelhouse in the left hand.

This playful aspect of Esfahani’s approach was even more evident in the four movements of Rameau’s Nouvelles suites de pieces de clavecin, especially in the final Gavotte et doubles movement where the variations build to a virtuosic climax.

But the harpsichord repertoire doesn’t end with the Baroque, although it was put on ice for a couple of centuries when first the fortepiano and then the pianoforte ruled supreme. Before its current revival, it is surprising to discover how many prominent 20th-century composers wrote significant works for it, including Poulenc, of course, with his Concerto Champetre for Wanda Landowska, Gorecki, Szymanski and de Falla.

American composer Henry Cowell lived through both world wars and came from an era when it was believed that the USA, untouched by the destruction in Europe and Japan, could lead the way to a new and optimistic era, culturally and politically.

Little known outside his own country, Cowell was in fact an important innovator, with even the great Béla Bartók himself asking him if he could use his theory of cluster harmony.

Those harmonies are deeply embedded in his 1960 composition for harpsichord, Set of Four, where they vie with forms and ideas from the Baroque period in a fascinating way with a distinct feeling of bravura. As you listen you feel the spirit of the early composers coming through – in the second Ostinato movement which is a little like Bach’s Passacaglia in C minor on methamphetamine, and the Chorale movement which leaves one with the feeling of being suspended between the old and the new.

Finnish ‘spectralist’ Kaija Saariaho was just eight when Cowell’s set was written. Her Jardin secret II, composed in the late 1980s in Paris when she was working with Pierre Boulez, pitches the harpsichord against an electronic soundtrack featuring vocals and manipulated concrete sound.

Here the instrument’s percussive qualities were fully exploited, making for a sense of two vastly different sound worlds colliding, finally ending in a slightly uneasy truce.

Proof, however, that the new can live with the old, especially when it is embodied by an artist who, like Esfahani, is always willing to explore and exploit those boundaries.