"Anybody could have done it. You just have to read carefully what Mr Beethoven wrote."
More recently, with Melnikov, cellist Jean-Guihen Queyras and the Freiburger Barockorchester, she has been exploring Schumann, first in concert and now on a Harmonia Mundi CD/DVD coupling the Violin Concerto with the last of the composer's piano trios.
"It was really thrilling for the orchestra. They had been thinking about changing their name since they haven't focused on purely Baroque repertoire for quite a while."
Faust brings up the challenge of tuning at a higher, modern pitch, necessitating new woodwind instruments. "But it was wonderful working with musicians who were discovering this music, moving on from the worlds of Schubert and Mendelssohn rather then approaching it from later experiences with Shostakovich and Mahler."
Schumann's Violin Concerto is "completely visionary", she says. "There's nothing more beautiful than its slow movement."
She enthuses over its opening Allegro.
"It's an absolute masterpiece, a mix of Don Giovanni and Baroque, with a lot of Bach coming through," as well as the ghost theme, returning in the Finale "sending shivers all over your body".
Faust has a daunting catalogue of CDs, including a marvellous 2012 recording of Beethoven and Berg Concertos with the late Claudio Abbado, who she met in the last six or seven years of his life and immediately realised, "Here was a man constantly looking for the truth in music, never simply relying on old convictions."
Abbado's meticulous preparation meant that "an orchestra would go along with him and create an experience that was like a journey to Heaven".
Faust is looking forward to working with French conductor Lionel Bringuier next week on the Mendelssohn Concerto, which she first played at the age of 15.
"I was 15 when I entered the Leopold Mozart Competition and, when I won, I realised I could now play as a concerto soloist."
The Mendelssohn was her first choice. "From the first note to the last, it's so perfectly shaped. It's so well-balanced and so new and fresh."
She draws my attention to Mendelssohn's many innovations, such as opening with the soloist playing that sinuous, shapely tune. She also admires the composer's own written-out cadenza "and the way those beautiful ricochet chords lead into the return of that first melody".
"It's been copied many times. Schumann does the same thing, not only in the Concerto but also in his Phantasie."
I ask about the instrument that will bring us this freshest of concertos next week, her 1704 "Sleeping Beauty" Stradivarius.
The nickname comes from the fact that "The family who owned it kept it locked in a cupboard for 150 years as no one could play it," she laughs.
"It's not earthy or velvety in sound. It's luminous, extremely clear and silvery, which makes it just ideal for Mendelssohn."
What: Auckland Philharmonia Orchestra
Where and when: Auckland Town Hall, Thursday at 8pm
