I was first struck by the scene’s arithmetic: one man; one piano; two sonatas; 900 audience members. I was then taken with how long Haefliger sat at the piano before playing. Those who appreciate music framed by silence would have approved of this.

Haefliger then eased into the Molto moderato e cantabile of Schubert’s 1826 Piano Sonata in G major, the composers’ expressive directions lovingly observed. The combination of long notes, dotted rhythms and rests between phrases lends this lovely opening a gentle dignity which I felt Haefliger captured nicely. Dignity not being the best spectator sport, the piece soon picks up. The following enlivened left hand figures were clearly articulated, allowing the soaring right hand melody in octaves to sing out. The repeats were observed, and there was then no mistaking the arrival of this sonata form movement’s development section. A double forte, downbeat minor chord announced the sudden switch from the lyrical to the dramatic. Further into this section, I was impressed by Haefliger’s seemingly effortless ability to project an inner melody in the right hand such that it emerged easily from filigree figures above and from the rhythmic accompaniment below.

The gentle three-note lead into the Andante would not prepare the first time listener for the movement’s central dramatic outburst. The opening D major is abandoned for a darker B minor; sforzando chords heighten tensions. However, a dramatic composer such as Schubert knew that listeners soon adapt to new moods, and he keeps us guessing – certainly regarding texture. In one of the lighter moments, Haefliger employed some lovely, subtle rubato to cast doubt upon the resolve and momentum of a four-note detached figure. The coda to this movement was played with winning delicacy, ending (like all the sonata’s four movements) pianissimo.

This quiet closure made the Menuetto: Allegro moderato’s opening seem all the bolder, its six-note, minor key chords suggesting a somewhat edgy dance. Haefliger’s colouring of the contrasting trio’s lighter, ornamental, B major cheer felt just right.

The first three movements having been unmistakably detached, the segue into the 4/4 Allegretto rondo finale momentarily threw me, until key and meter made it clear what was happening. Once more, Haefliger’s sensitivity to Schubert’s feel for the surprises of key, mood and colour was impressive. Having resumed the home key of G major we are, in fact, far from settled as Schubert whisks us on a mini-tour of E flat, C, and E flat before returning us home. This was fine playing and the audience responded warmly.

Schubert’s gentleness was followed and complemented by the relative ferocity of Beethoven’s Piano Sonata in B flat major, Op. 106 “Hammerklavier” (1817–18). Having spent a rainy interval reading Misha Donat’s learned notes, I was certainly looking forward to revisiting the piece, the Adagio of which he described as “surely the most sublime piece of its kind Beethoven ever wrote for piano”.

Like the Schubert, it opens with dotted phrases separated by rests. However, the fortissimo dynamic ensures that gentle dignity is that last thing on our mind. In fact, we didn’t have to wait long for what Donat described as “almost superhuman demands on the performer”. Those who have played or listened to this work will know that it has everything: big chords, octaves (struck both simultaneously or, like boogie-woogie, alternating the upper and lower notes), counterpoint, trills, sudden and gradual dynamic contrast. Much of this occurs at extremes of the keyboard and the journeys are not always gradual. Despite Haefliger’s mastery of the movement, it occurred to me while watching that, were playing from memory not performance convention, it might be a survival necessity in this piece, which surely relies on the eyes.

The “joke” element of the Scherzo may well be its rhythm. Although the triple meter theme begins on beat three, it could be perceived as beat one, a confusion not cleared up by the off-beat pedal notes which follow. Hearing the Adagio which follows, one is glad to have had some light relief. Experiencing Haefliger’s performance, I could understand a remark in the programme likening Liszt’s interpretation of the movement to “an eyewitness of secrets of a world beyond the grave”. This reading felt perhaps less sepulchral than otherworldly, in the manner of Beethoven’s late string quartet slow movements.

The dramatic peak was the final fierce fugue, which was truly gripping. Audience response was energetic, and many got to their feet. Haefliger's bow was long and deep, taking care when he rose to make eye contact with each zone of the Queen’s Hall’s two-tier horseshoe. And soon, for the second time in 48 hours, its much loved acoustic would house Isoldens Liebestod, Liszt’s arrangement of the final scene from his son-in-law, Wagner’s opera Tristan und Isolde.