Idomeneo, Barbican, London

Saved from shipwreck by the gods, King Idomeneo promises a blood-sacrifice but discovers the victim must be his son Idamante; Trojan princess Ilia is torn between love for Idamante and hatred for Idomeneo (who has killed her father); jealous Elettra also loves Idamante; a monster must be slain, and a deus ex machina waits in the wings...

Mozart's first operatic masterpiece is about the voice as a vehicle for emotion, rather than about plot, and he laboured mightily to realise this with his original cast. But it was uphill work: his Idomeneo was well past his prime, and his Idamante was so inexperienced that he had to coach him like a child. "That boy has no ability whatever," Mozart wrote to his father, going on to reveal what he looked for in his soloists: "He has no intonation – no method – no feeling."

There were no such problems with the team fielded by violinist-conductor Fabio Biondi in this concert performance at the Barbican. Led by Ian Bostridge in the title role, these principals were both a stunning combination and a perfect complement to Biondi's brilliant period-instrument ensemble, Europa Galante, and fastidiously drilled chorus. And it was a positive pleasure to focus on the sound: with music-drama of this clarity and intensity, you don't need sets and costumes. "Concert staging" is enough, provided your singers are dramatic.

Launching into Ilia's opening lamentation, the regal-looking Kate Royal produced a big, noble sound, answered by Jurgita Adamonyte's silvery, vibrato-free mezzo as Idamante; when that consummate drama-queen (in the best sense of the word) Emma Bell opened up as Elettra, we had three contrasting voices in an unusually piquant blend. I had not heard tenor Benjamin Hulett before, but even in the minor role of Arbace his warm, supple sound was a revelation; Bostridge – currently being feted at the Barbican as the voice of the age – was in a company of equals.

Indeed, for the first two acts he seemed less into his role than the others: his artistry was immensely accomplished, but he didn't touch the heart as he should have, nor did he seem to be wrestling with inner demons. But as we approached the quartet that is the opera's beating heart, he too seemed carried away by the searing emotions that Biondi had so skilfully pricked into life.