On the basis of its length alone, Verdi's Don Carlos is the grandest of the composer's grand operas. So vast was the work that Verdi cut swathes of the music even before its Paris première, to allow audience members to catch the last trains home well after midnight. Evidently, such significant undertakings do not phase La Scala. The opera house has opted for the longer five-act version of the work written for Modena, which here came to six hours of entertainment when the three scheduled intervals we had are factored in. Were it not for a sterling musical display, built on the shoulders of bass Ferruccio Furlanetto and conductor Myung-Whun Chung, this could have been a very long night indeed.

Peter Stein's period-costume production does little to sustain us through this operatic marathon. He gives us vast open spaces skimmed with minimalist form, bolted together with plywood screens, hulking centerpieces and shoddily-produced projections of roaming clouds. What might be a search for dramatic clarity translates merely as vagueness, so that stacks of logs in an anaemically-lit Fontainebleau Act, for example, might have stood for anywhere but a gloomy forest. Stage-direction is equally starched. An enraged Eboli, sung by Ekaterina Semenchuk, flings herself against a wall histrionically when denounced by King Philip II. A risible parade of racial stereotypes in oriental headgear and sombreros plods ontsgage for the Auto-da-fé, then remains on a grandstand for longer than we would have hoped.

The pressure is therefore on the cast to conjure the magic itself. This production's original outing at the 2013 Salzburg Festival boasted a star roster, here matched for strength and depth with La Scala regulars in abundance. Francesco Meli's Carlos had open, full-throttle sound on full display by the time we reached “Io l'ho perduta!”. Krassimira Stoyanova provided a multi-dimensional account of his unobtainable love Elisabetta di Valois, combining the noble poise of woman that has gracefully accepted her lot with sumptuous vocalisation and flashes of human fragility. Meli might have benefited from greater directorial input whenever alone, but he and Stoyanova sparked off one another vividly, providing a narrative that bridged burgeoning love in the Forest of Fontainebleau to deep mutual pathos at the work's finale.

The young baritone Simone Piazzola as Pola reminds that the new generation of Italian singers is well-stocked for talent. He delivered intelligently-crafted text in golden tone and streaming legato, put to good effect in “Io morrò, ma lieto in core” to cap off a convincingly-acted death scene. Piazzola apparently realises two dreams in this production: to perform Don Carlo at La Scala and to sing alongside his boyhood hero bass Ferruccio Furlanetto. The onstage rapport of the two was another performance highlight, Posa resisting the Filippo's entreaties with authority, and Furlanetto sending a chill down the spine with whispered intimations of the Grande Inquisitor's nefarious intentions.

It was indeed Furlanetto that formed the pillar of this stage performance. Near on four decades after making his La Scala debut, his oaken voice remains in fine working order, and it is hard to imagine a more convincing performance of this hectoring King gnarled by paranoia. This was an intimidating portrayal of the role, albeit one laced with vulnerability via a moving “Ella giammai m'amò”. That said, nothing terrified more than his confrontation with Eric Halfvarson's Grande Inquisitor: pure fanatical rage funnelled through an age-wracked body.

The performance of Myung-whun Chung, a consummate Verdian, was nothing short of revelatory. Rapping rhythms and blazing brass were taut and incisive, just as they should be, but it was in the score's lyrical portions that Chung was at his most sublime. Breezy tempi were spot on yet invested with special malleability. Solemn brass for the introduction to Act IV yielded to incandescent strings, catching a gust of wind and soaring skywards. When staging left much to be desired, we were grateful to have been provided this fine musical display.