Sunday night at the Royal Festival Hall found a large audience collecting for two very special performances. The evening opened with the first two movements of Schubert's “Unfinished” Symphony no. 8 in B minor. The Philharmonia Orchestra, from the very first bars, exhibited a superb sense of unison and timing, with conductor Josep Pons often stepping, even crouching, in the direction of each section of the orchestra to encourage and engage. Occasionally, Pons was actually lifted entirely off his feet by the vehemence of his gestures, conducting with his entire body, from the tip of his baton to the soles of his shoes.

However, mere accuracy was not their only achievement: Pons' sense of powerful control served to underline the deep emotional colours of this piece, music whose tremulous idea of hope is rooted in, and stumbles into, continual fear. In the Allegro moderato, the string section excelled: the cellos felt like the narrative force, while the violins added emotional context, and we had glorious softness and smoothness even in the darkest moments from the double basses. The vehemence of Schubert's writing in his first movement reminded me in flashes of Mozart's Don Giovanni Overture, or the bitter dance themes from Verdi's La traviata; by contrast, Schubert's Andante con moto was so rapturously romantic that it sounded like Massenet, its initial warmth soon developing into anxiety and blossoming pathos. Gradually, Schubert evokes an imperious sense of peril, with reciprocal themes making rising patterns inside the score between different instruments, contrast and echo becoming key preoccupations in the music. Pons' supreme control and the Philharmonia's enviable unity ensured they could switch from stormy seas to calm waters in an instant, as Schubert began to sound (and feel) more like Strauss to close, the emotional landscape becoming ever more sophisticated and dark.

Whether this superb account of Schubert did, in fact, put the large Royal Festival Hall audience in the ideal frame of mind for Mahler's mysterious Das Lied von der Erde is something I still can't quite decide. I'm now in two minds about this work: on the one hand, it is unquestionably a powerful vision of existential angst, with soaring vocal expression set above a sometimes painfully difficult, sometimes miraculously beautiful score. On the other, the very rootlessness of its existential theme is a danger for any audience: it can make the piece feel like mere intellectual posturing, while its lyrics (inspired by the highly stylised work of Tang Dynasty poets) can seem brittle, trite and repetitive, rather than elegant ideas of eternal relevance. Despite my private uncertainties about the work itself, however, I cannot imagine it better sung or played than by Pons' strong team of the Philharmonia, tenor Robert Dean Smith, and mezzo Catherine Wyn-Rogers.

Robert Dean Smith's warm and lyrical tenor took a little time to establish itself over the orchestra, but soon found success, mainly thanks to his supple upper range and the fullness of his tone. Over lovely orchestral colours and shimmering harmonies, Smith gave a gently characterised, rather than fully acted, performance which sounded by turns charming and triumphant; the tenor has to coexist with some painfully aggressive orchestration from Mahler, whose writing is occasionally angry, disorientatingly busy or just plain loud, but Smith did not get thrown off stride, and maintained a joyful sense of beauty throughout.

Matthias Goerne's unfortunate indisposition was amply made up for by a stellar performance from Catherine Wyn-Rogers, her superb mezzo clear, strong and vivid. Acting more fully than Smith, although neither voice appears to have been given a specific narrative role by Mahler, Wyn-Rogers seemed admirably immersed and utterly confident in all her songs, which she had taken on at short notice due to Goerne's indisposition. Her opening lines of "Der Abschied" were particularly magical, with wonderful oriental colours throughout from the Philharmonia, particularly the woodwind section, creating rippling movements and lyrical melodies; every song was a treat, some feeling like stories, others like tone poems.

Beautifully executed in every possible sense, Das Lied von der Erde remains, for me, a bewildering and mysterious piece; but maybe that is simply the point. A tidal wave of enthusiastic applause from the audience to close clearly indicated that, however strange it might be, and whatever the piece really is, this team had definitely hit the mark with a performance of consummate skill.