If you're not going to mention the imaginative genius of Stravinsky, Auden and Kallman within the covers of your programme, and the only article, by the director, is titled "Acting Naturally", then the production had better deliver.

It has long been a mystery why no new production of Semiramide should have been staged at Covent Garden since 1887: un offesa terribile considering that this splendid melodramma tragico should have been the inaugural production of the Royal Italian Opera House (our current theatre’s predecessor) in 1847.

The great and good of the London music scene were gathered at English National Opera last night for the unveiling of American Wunderkind Nico Muhly’s new opera, Marnie. Although it was commissioned by the Met in New York, somehow ENO managed to wangle the world premiere, which has been widely hyped and was ecstatically received by a packed house. But for all that there was much to enjoy, it hardly deserved such rapture, and there were problems with both piece and production.

Katie Mitchell’s production of Lucia di Lammermoor opened at Covent Garden in 2016 and now returns for a first revival. Royal Opera were clearly expecting great things, even from the start, and this is the third cast to have presented the show, after two separately cast runs last year, and a commercial DVD is also available. Mitchell has repaid their confidence with an impressively conceived production: visually arresting, suitably dramatic and with many subtle narrative additions.

Fancy that: the day after the last major Menotti staging I can remember in the UK, The Medium at the Edinburgh Festival, "splendid piece of post-Puccinian grand guignol" turned up in two different reviews (moral: don't discuss the performance with your colleagues). "Dated piece of post-Puccinian absurdist melodrama" might be a bit harsh but not so wide of the mark in the case of The Consul, his late 1940s fantasy rooted in the horrors of totalitarianism and western bureaucracy.

Singing students from the Guildhall School should have been issued with a three-line whip to fill the inexplicably half-empty Milton Court concert hall for last night's charmer. After all, every musician, and not just sopranos, should know that this is how it ought to be done. True, an effervescent personality like Lucy Crowe's can't be simulated. But every other respect of her stunningly sung and varied Mozart can be aspired to: the relaxed, natural stance (and in this instance, knowing how to play a recalcitrant shoe heel for comedy), knowing what to do with the hands, how to execute coloratura as spine-tingling expression, not mere display, how to spin long lines and to colour the music according to the situation, with the right dramatic looks and widening of the eyes to match.

True, this was culinary Mozart of the sort to make E F Benson's Lucia and Georgie affectedly exhale, two-thirds of it composed in his teens, but as with Donizetti and Bellini, when you have supreme stylists in charge, it all commands attention. There are no better period-instrument players around than Harry Bicket's band, and though the dry acoustics didn't help them out in the way that the Wigmore Hall would in the frothiest of Mozart's early Divertimenti, the D major K136 with the already-vintage humour of its six-note finale kickoff, the pleasures came thick and fast. Mozart's inner string lines were full of life and interplay, runs clean and bright.

The orchestral counterpart in the concert's second half, the A major Violin Concerto K219 with its rollicking "Turkish" rondo episode, brought another pleasure of collaboration. The English Concert's leader, Nadja Zwiener (pictured left), may not be a born soloist with the kind of panache that Isabelle Faust brought to the even slighter G major Concerto at the Proms, and in her first entries she had a bit of an intonation problem as well as less than perfect ornamentation. But the Adagio shone with such a rare consonance between violinist and orchestra, the sort of thing that star players flying in for one rehearsal can't achieve, and by the finale, with aforementioned romp both clearly articulated, with none of the usual rushing, and laugh-out-loud exuberant, we were back to the level of what Crowe had already achieved with Bicket and co (the conductor-instrumentalist pictured below by Richard Haughton).

Our great soprano didn't make it easy for herself, plunging in with Aspasia's ferocious first aria in Mitridate re di Ponto. If Crowe had been singing this role rather than the less rewarding one of seconda donna Ismene at Covent Garden, that musically rather ordinary evening might have come up to the mark of this one dazzling performance. More brilliant still was "Ah se il crudel periglio" from Lucio Silla, with its unbelievably well-executed runs in the recap.

The necessary breather in between was the lovely "Ruhe sanft" from Zaide, Crowe touching and perfect of legato phrasing in dialogue with Katharina Spreckelsen's cool oboe obbligato. The maturity of Mozart begins to shine through here in the extra beauties he finds in the instrumental coda, and by the time of the "Et incarnatus est" from the great but unfinished C minor Mass, we are in vintage territory with not only that effortlessness of vocal writing but also the woodwind ensemble, enriching what becomes a kind of quartet-cadenza of melting beauty.

Crowe also made the heart flip in the simpler, solo cadenza at the heart of "Exsultate, jubilate". Each time I've heard her sing it, not a note or a phrase has been out of place, and this was on the same level as last year's glorious performance with David Bates and La Nuova Musica. The bonus proved simply sublime, making the eyes prick as the earlier numbers could not: as Bicket pointed out, Mozart by the end of his life knew how to say with 40 bars what had earlier taken him 200, and with Crowe bringing extra fullness of tone to what is usually just a pretty arietta, Servilia's "S'altro che lagrime" from La Clemenza di Tito, we all too few in the audience came out knowing we'd heard the best that singing in concert has to offer.

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