At Worcester Cathedral last night, it was a concert of two halves. One half comprised what may well have been the highlight for many in the audience: Janáček’s Glagolitic Mass. There have been settings of the liturgy that rival this work in terms of unconventionality, ostensible irreverence and all-round callithumpian mischief, but not, surely, as early as 1927, when the work received its première in Brno. Taking its name from the fact that it sets the words in old Slavic – known as Glagolitic script, dating back to the 9th century – the Glagolitic Mass is as confounding as it is contagious. Even in its brief but curious introduction, spasmodically switching between figurations while maintaining a grand demeanour, Janáček makes it abundantly clear that what’s to come will defy all expectations.

It would be easy for a performance of the work to turn into a kind of St Trinian’s-esque romp, the orchestra leaping around, running riot while the singers – chorus and soloists alike – squawk and shriek and bellow with abandon. Conductor Frank Beermann impressively found a way to keep a lid on all this pent-up mayhem while nonetheless allowing everyone on stage the freest of reins. Thus, the Kyrie was so full-blooded that its confidence in the mercy being petitioned for was overwhelming, becoming a complex simultaneous outburst of desperation and elation. The Gloria went further, Beermann eliciting such a sense of euphoria that the music was practically beaming from ear to ear as it ran and tumbled, surrounded and suffused by glory, the chorus letting fly enormous exclamations somewhere between singing and shouting, caught up in rapture. Even the Credo, surely one of the least promising texts for any composer to have to make musical, became akin to a jaunty swaggering along a promenade in the fresh air, ultimately even seeking to outdo the Gloria in the boisterous, cavorting shapes it pulled. It was tempting to applaud after every single movement.

That the soloists were able not merely to be audible but actually to ride upon and soar over such enormous waves of sound was no small achievement; all four were impressive, soprano Natalya Romaniw and tenor Daniel Norman especially so, like a pair of generals issuing commands to an army. Beermann handled the work’s conclusion perfectly, bringing down the Philharmonia and Festival Chorus through the Sanctus and Agnus Dei to a point where we believed humility might just be possible. Whereupon the famous organ solo and orchestral climax blew such notions to smithereens in an overblown finale of histrionics and hysteria. Not so much an act of worship as an exercise in shock and awe, ninety years on from that first performance Janáček’s Glagolitic Mass has clearly lost absolutely none of its weird but undeniable power.

In many, if not most, concerts one would come away with that piece proving to be the most impressive and memorable. However, the other half packed a punch – albeit of an entirely different order – that was easily its equal. Torsten Rasch’s song cycle A Welsh Night, being premiered in its new orchestral version, brings together six texts drawing on poems by Alun Lewis. On the one hand, there were times when one wondered if Rasch’s enthusiasm, seeking to tease out everything possible from the words and wring them dry, had led to a somewhat overuse of instrumental colouration. This was reinforced by the number of times when mezzo-soprano Susan Bickley was unable to make herself heard over the orchestra. Yet there’s a great deal packed inside Lewis’ words, and in any case the nocturnal, even sepulchral, emotionally-charged sensibility that Rasch creates in the work is utterly immediate. The transparency of the Philharmonia’s performance was exquisite, a superbly-judged balance of delicacy and dread. One could rationalise that Bickley’s occasional inaudibility only made the ominous undertone pervading these six songs all the more evident, the combination of vocal fragility and orchestral threat.

Reduced in size yet further, just 23 players remaining on stage, the most telling music of the evening was Strauss’ Metamorphosen. Completed in April 1945, his native Germany in ruins, Strauss taps into something far beyond mere sadness, an all-enveloping, post-apocalyptic melancholia. Yet, somehow, the piece sings – obsessively, relentlessly, born out of nothing less than an unshakeable need to sing in the midst of such abject desolation. The Philharmonia made Worcester Cathedral feel small and intimate, Beermann again judging the tempo just right, an effective briskness that avoided any hint of wallowing or milking. As the work cycled round and round its small collection of melodic ideas, metamorphosis happened, impossibly transforming from profound sorrow to a place of tear-strewn hope. Yet as it inexorably faded back to black, its Wagnerian woe was rendered with heart-stopping poignancy. Here – unforgettably – was infinite, crushing pain.