Roméo et Juliette, BBCSO, Davis, Barbican

It was another Davis, the late Colin rather than the very alive Andrew, who used to be master of Berlioz's phenomenally inventive opera for orchestra with its novel explanatory prologue and epilogue. I like to think he'd have been looking down fascinated by last night's very different miracle of pace, clarity and ideal blend of instrumental and vocal song.

Shakespeare might have approved of what he'd inspired, too, though like rather a lot due to happen in the 400th anniversary year, hardly any of his words are to be found here; this is Berlioz's "What I feel about Romeo and Juliet". Once past the grab-you-by-the-throat string fugato at the start – warring Montagues and Capulets kept light and springy rather than bloody-brutal in this performance – a semi-chorus keenly etched by singers from the BBC Symphony Chorus and two soloists tell us what's going to happen, and the orchestra obliges with snatches of things to come.

Davis's theatrical sense of continuity brushed aside any questions of "When are we going to get there?", and there could have been no more exquisite singer of the superfluous but lovely ode to first love and Shakespeare than mezzo Michèle Losier (pictured above), subtly accompanied by that supreme harpist Sioned Williams. You really wanted Losier to come back and sing an encore, Berlioz's "La mort d'Ophélie", for instance, in a new orchestration. But that was her over and done with, alas, and tenor Samuel Boden despatched his promise of Mab, queen of dreams, in a spot-on flash and was gone.

So to the orchestra to sigh, swoon and dance in the central drama. There are too many solos to mention in Berlioz's cornucopia of invention, which changes virtually by the bar, but oboist Richard Simpson sang his heart out as Romeo alone, climbing to ecstatic heights, and later clarinettist Richard Hosford provided the plaintive opposite in the cries and whispers at Juliet's tomb. The central love scene may have been less atmospheric than some, but always sure of purpose, which past the peak was an asset when the exact object of Berlioz's tone-painting of the balcony dialogue isn't always clear.

Davis and his strings especially had to be on tiptoe throughout the greatest wonder of all, the gossamer fantasy of Mab's dream antics – the woodwind spookiness haloed by harmonics was to inspire another Shakespeare fantasy, Verdi's image of Nannetta as Fairy Queen in Falstaff – and, just when you thought the futuristic invention couldn't go any further, the orchestra's vocalising at extremes for the two suicides proved hair-raising.

Sometimes you question the wisdom of Friar Laurence's lengthy final plea for reconciliation over the bodies, but not with bass David Soar (pictured above), both sensitive and stentorian – a magnificent successor to the likes of Robert Lloyd and John Tomlinson – and the full BBC Symphony Chorus blazing very precisely. Original to the last, Berlioz gives us a peroration which could have been banal but instead takes interesting twists and turns. And Davis left us in no doubt that this was a necessary goal of a masterpiece which seemed more than usually shapely last night.

• Listen to David Nice's BBC Radio 3 'Building a Library' on Berlioz's 'dramatic symphony' on iPlayer
• Listen to the concert for the next month on the BBC iPlayer