This year, John Copley's 41 year old production of La bohème is on its last outing, with the Royal Opera marking the occasion by casting the big name pairing of Joseph Calleja and Anna Netrebko as Rodolfo and Mimì (later in the run, none other than Plácido Domingo will be conducting). So the evening carried a fair sense of occasion.

After 27 revivals, there's nothing new to be said about Copley's staging, so I'll limit myself to reminding you of the strengths that have made it so popular and a benchmark for staging of verismo opera. Just as Giuseppe Giacosa and Luigi Illica's libretto is obsessive in its attention to the details of the way people behave, the late Julia Trevelyan Oman's sets and costumes are obsessive in their attention to period detail. And Copley's direction is remarkably free from dramaturgical error: everything just works. It's a staging that makes it particularly easy for actors/singers to inject realism into their performances and acting was generally good this evening, although short of the best: I’ve seen the jokes crisper, the lovers more ardent and the despair more authentic.

Vocally, however, the evening was excellent. Calleja and Netrebko are both notable for exceptionally attractive timbre, and both duly delivered. It’s fascinating to compare Netrebko’s voice now to what it was, say, five years ago: the crystalline brightness at the top has reduced, to be replaced by a full, rich glow through most of the range, while the excellence of technique remains: she develops a phrase beautifully, with subtle shifts of voice adding a series of colours. Calleja, for his part, embodies the virtues of traditional Italian tenor singing: warmth and generosity of tone coupled with a voice that never seems to strain. Lucas Meachem, who sang Marcello, shares many of these qualities with Calleja, albeit at the lower baritone level: their Act IV duet, as Rodolfo throws away his pen and Marcello his paintbrush because neither can bring themselves to work, was one of the vocal high points of the evening. Making her Covent Garden début as Musetta, Jennifer Rowley gave an assured performance vocally. I did feel that she rather overacted the part, which I hope will settle down as the run progresses.

As ever, the Royal Opera are able to ensure that supporting roles were strongly cast: Simone del Savio sang and acted an urbane and likable Schaunard, while Marco Vinco gave a fine rendition of Colline’s paean to his old coat “Vecchia zimarra, senti”, one of Puccini’s lovelier bass arias.

The disappointment of the evening was the orchestral performance. Dan Ettinger seemed most comfortable when the music was bright and upbeat, able to bring lightness and airiness into the playing. But he was less convincing in the quiet passages where what we want is snatches of individual instrumental colour shining out. And the orchestra were uninspiring in the area that most characterises La bohème, its grand sweeping romantic phrases. When you are not gathered up and swept away by the lushness in the combination of voices and strings, you are not hearing this opera at its best.

So it’s time to look forward the Royal Opera’s new Bohème, due in 2017/8. It’s unlikely that any new production will beat Copley for limpet-like attachment to the detail of the original work and for sheer stagecraft, so let’s hope that the new production provides us with something totally different that casts new colour and style onto this most popular of bittersweet operas. And still – as last night did for me – leaves us choking back the tears at the final curtain.