Alzira, Verdi’s eighth opera, is something of a discarded child within his canon, not least because of Verdi’s own dismissal of it as “proprio brutta” (really ugly) after it was poorly received both in Naples and Rome. Perhaps Verdi was stung by a blot on an otherwise successful career: on the basis of last night’s concert performance by Chelsea Opera Group, the score has plenty to commend it.

The Voltaire play on which Alzira is based was intended, like many of Voltaire’s works, to explore the differences between true humane goodness and the surface gloss of Christian religiosity: set in the Peru of the conquistadors, both Spaniards and Incas show brutality and nobility at different times. Salvatore Cammarano’s libretto starts out somewhat in tune with this, but degenerates rapidly into a standard operatic love triangle: the Spaniard Gusmano, a fine baritone villain, will resort to all possible abuses of power to wrest the beautiful Inca princess Alzira from her betrothed (dramatic tenor) Zamoro. You can think of it as a prototype for Cammarano and Verdi’s subsequent and far more enduring collaboration Il Trovatore, minus the gypsy element and plus a sympathetic older generation consisting of Gusmano and Zamoro’s parents, who join in some stirring ensemble pieces.

This is the second time in three days I’ve seen conductor Gianluca Marcianò, and the second time I’ve been really impressed. The man is a fireball on the podium, bursting with energy. His legs seem on springs as he often dances to the music with an enthusiasm that’s clearly infectious; the orchestra responds with verve and bright colours – and yet there’s clearly an excellent element of control, with tempi never feeling rushed, the music never getting too loud and brash. Tbilisi State Opera, where Marciano is Musical Director, may not be the best known company in Europe, but for me, they’ve made a real find.

This being a concert performance, there’s no staging or acting to worry about, so it’s possible for singers to focus entirely on musicality and delivery of the text. Mark Holland gave a sterling performance as the villainous Gusmano, a Verdi baritone role very much in the mould of Trovatore’s Count di Luna, with an appropriately dark voice colour and a way of always making you feel that there were plenty of reserves of strength behind what you were hearing. As the heroic Zamoro, Mario Sofroniou sang the lyrical numbers attractively, with a pleasant, clear voice which never sounded strained. It was a thoroughly professional performance, albeit lacking in that sense of risk-taking abandon which adds real excitement to a Verdian tenor part: you want a Verdi tenor to be just a little closer to the edge of what his voice can do. The title role isn’t an especially rewarding part – Alzira does little except sing at how unhappy she is to be passed around as a chattel/how happy she is to be united with Zamoro – but Majella Cullagh sounded great, with plenty of power, plenty of warmth and some real grace in some of her phrasing.

The Chelsea Opera Group is an amateur company, but I’d have been hard pressed to spot it from the playing of the orchestra. Alzira has some great pieces of orchestration, particular highlights for me being the overture and the passage in Act III where the remnant of the defeated Inca army is gathering in a cave, and the playing was up to the very highest standards. Sadly, I can’t say the same for the chorus. They felt a long way away, standing high behind a substantial orchestra, and they simply didn’t generate the power or clarity to make themselves properly heard. Marcianò made strong efforts to ensure the orchestra didn’t overpower the singers, but I suspect that he rather gave up on any efforts to take them down below the chorus’s level.

If the base material of Alzira is no more than average, Verdi’s treatment of it is not, and last night’s cast and orchestra made a very good case for it, and I ended the evening in complete agreement with Chelsea Opera Group’s assessment that it has been unjustly neglected. Alzira may lack set pieces that are as memorable as those in Verdi’s more famous operas, but as ever with Verdi, his ability to conjure up drama from the interplay between characters lifts the work from mediocrity into a thoroughly entertaining evening’s opera.