First there was an announcement informing us Ms Prohaska hasn't been feeling well for the past few days, then an unnervingly long wait for the Austrian soprano to appear on stage.
When she did, though, her opening lines were fearless. She sang a foreboding German folk song ('Es geht ein dunkle Wolk herein'), her rendition quiet, unaccompanied and unblinking. What a striking start to her Edinburgh debut.
This recital was a superbly-conceived programme of 25 soldiers' songs taken from her recent Deutsche Grammophon album Behind the Lines.
With sturdy supportive piano playing from Eric Schneider, Prohaska's dramatic imagination was evident in every detail of her performance.
She even dressed in costume, looking sombre and vaguely androgynous in a black double-breasted jacket and breeks.
Lurgy or no lurgy, her voice was beautifully coloured. Maybe she lacked a little bloom on the upper notes, maybe her consonants were stickier than usual, but if this is Prohaska in poor form she is a robust singer indeed.
Her way with text is especially vivid - she flitted between songs in German, French, Russian and English without a pause and she captured the character of each without ever resorting to sensationalism.
Her diction is subtle enough to distinguish between the American drawl of Charles Ives (In Flanders Fields, 1,2,3, Tom Sails Away) and the Elizabethan English of Michael Cavandish (Wand'ring in this place).
She even conjured a fine Scots accent and ornamentation in Thomas Traill's 17th-century lament My Luve's in Germanie. She was sassy (but not too sassy) in Kurt Weill, tender in Schumann, flamboyant in Liszt. Little wonder Prohaska is being tipped as one of Europe's most exciting young voices.
I, Culture Orchestra
THERE are plenty of other reasons to be fascinated by this new West-facing East European youth orchestra, nurtured in Poland and involving young musicians from Armenia, Azerbaijan, Belarus, Georgia, Moldova and Ukraine, especially at this time.
But to be despicably shallow for a moment, this will surely be the most attractive orchestra to appear at this year's festival, its membership at least 50 per cent female - in full-length black gowns - in all sections bar brass and horns.
They sound as good as they look too.
It is a mark of a great orchestra that it makes you hear in a new way famous moments - such as the entry of the side-drum-underscored, repeated theme on the strings in the epic first movement of Shostakovich's Leningrad Symphony - and that was what happened here.
Perhaps it should not have been a surprise, because the ensemble string sound achieved by the young musicians of I, Culture is first rank.
That movement builds to one of the most thrilling climaxes in all music.
Conductor Kirill Karabits made sure his charges gave us every ounce of it.
The journey of Shostakovich's Seventh doesn't end there though, and Karabits kept the momentum up all the way to the finale with its strong, defiant and eventually triumphant repetition of phrases of few notes.
The orchestra proved its strength across the board with fine solos from the principal oboe, flute and especially bassoon - all female - and precise, focused brass, made up of 14 players, all of them male.
Less well-known, but well worth hearing, was Polish composer Andrzej Panufnik's musical essay on the pity of war, Sinfonia elegiaca, whose central, less elegiac central section was dramatic and filmic, and superbly performed.
This review appeared in later editions of yesterday's Herald