Norma, English National Opera

In the light of what follows, it's probably best to be clear that I'm completely behind the artistic side of ENO in rejecting a 25 per cent reduction of the chorus's annual salary, tied to a shorter season. A full-time chorus of this size is the heart of a big company – without it, no Mastersingers, no Grimes, no Lady Macbeth of Mtsensk.

A creative alternative solution must be found. Musically matters stand stronger than ever, with the new regime's most recent hit being a transformation of what was originally a lame-duck Magic Flute. Production wise, this Norma is one of the old guard's poorer choices. The good news is that the old guard's casting actually saves it.

There has to be one very strong reason for ENO putting on not terribly music-theatre-friendly hokum like the early-19th-century Italian bel canto operas sung in English: namely a soprano who can hold her own against the pricier stars available to the Royal Opera. The company's Lucia di Lammermoor painfully lacked a beating heart in Anna Christy's doll-like heroine. Now, though, the track record for engaging strong American singers which began this season with Patricia Racette's Katerina Izmailova and continued with Tamara Wilson's revelation of a Leonora in The Force of Destiny is crowned by Marjorie Owens as Bellini's Druid priestess who's broken her vestal vows (pictured below). In a double coup, her unwitting love-rival Adalgisa is every inch Owens's equal in the astonishing performance of mezzo Jennifer Holloway.

The duets between these two ladies make or break any Norma and have a dramatic backbone that's otherwise lacking in Bellini's hit-or-miss opera by numbers: there's the tension that for a while they don't know they're backing the same shit as a lover, ignoble Roman Pollione, that Norma needs to reveal the two children by Pollione whom she's miraculously been able to conceal from the cult and that Adalgisa needs to convince Norma of her sisterly devotion. The second, and greatest, duet in Act II is also one of the few stretches where director Christopher Alden, in a production first seen at Opera North in 2012 (so ENO were warned), doesn't break focus with someone else flumping or crashing across the stage doing something inappropriate or unintelligible. 

In that respect you have to pity Valerie Reid as Norma's confidante and child-help Clotilde, at one stage staggering around with a sickle like a cartoon harpy of the French Revolution – the period in fact is mid-Victorian, ask not why – and Adrian Dwyer as Flavio, Pollione's similarly top-hatted sidekick, an arrogant over-present henchman doomed by Alden to a nasty but still rather risible end.

Chief "druid" Oroveso for some reason manipulates the action for as long as he can, and has to hang around on stage way too often, but at least this gives the opportunity to James Cresswell (pictured below with Owens), more or less the resident company bass this season, to let rip with the magnificent timbre which he's been reining in as a believable (if also cultish) Sarastro. There's also much stumbling and fruitless aggression demanded from the chorus, who – it should go without saying these days, though the management is deaf to the fact – provide their usual irreplaceable company spirit in singing some rather dull numbers extremely well. Alden was right to bring them forward for a special second bow at the curtain call, but the roars which greeted their first had already spoken volumes.

Set Bellini's fitful drama when and where you please, but give us a moon and a sacred wood, not just wood – the setting seems to be a large rural barn with dangerous farming implements hanging on one wall and a smithy below them– and daylight coming through two high, small windows. You know from the start you're not going to be rid of Charles Edwards's one-size-fits-all design – not a patch on his Royal Opera Elektra – or that giant phallic log with which only Holloway's Adalgisa has any meaningful relationship. Peter Auty, a clarion tenor from the start in a thankless role, has to straddle it (why?) and Owens needs to climb it to sit vatically on a precarious chair for what will forever be "Casta diva", her rather splendid Victorian dress covered with cult symbols billowing (rather handsome work there, all the same, from costume designer Sue Wilmington).

Owens's first offstage recitative proclaimed a vibrato that could be worrying for the long bel canto lines, and some odd vowel modifications in the upper register for George Hall's well-fitting translation, but reservations dissolved within minutes of the great hymn to the moon. You know whether you're in safe hands or not when the climactic phrase rises to a top B and the soprano has to cling on to it, ff, before hitting the C and descending; not to lose pitch at this point shows a secure technique, and Owens has that in spades. She combines the near-impossible in the role – declamation fit for a Brünnhilde or Isolde and coloratura precision. 

You don't expect limpidity in this space, and neither Owens nor Holloway, when combining in liquid thirds, offer much of that, but their voices are a perfect match for each other, and without an equally strong Adalgisa the show is lost. Holloway, in other words, is its crucial lynchpin and saviour. Stephen Lord's conducting, riveting the attention and drawing unexpected colours from the ENO Orchestra in a prelude which we hardly notice isn't great music, supports and moves with his singers well enough, though lacking the last degree of Italianate rubato and natural gear shifts.

At the end of the first act, Alden has his Norma sit there with an axe, as if we're going to move on to Strauss's Elektra after the interval. Of course it's shades of another Greek heroine, Medea, whom Bellini and his librettist Romani invoke as the wronged secret wife thinks of avenging herself on her man by slaughtering their children. She doesn't – no plot spoiler there – and she wastes the strong feminist stance of Adalgisa in rejecting the cad by wanting to return to him.

Well, that's Italian opera; but if dramatic and musical truth flourish only fitfully in Bellini's best operatic shot, we've had our vision from the two great scenes of female sorority. And yes, ENO chose well in its voices yet again. Usually a poor production would knock a star or two off the singing, but in Bellini acting with the voice absolutely has to come first, and here it does. Now hurry up and sign the petition from 'the Spirit of Lilian Baylis' if you haven't already done so. This kind of collective energy can't be squandered; once it's diminished, it's lost for ever.

• Norma at ENO until 11 March
• More about recent ENO happenings on David Nice's blog