There may have been a historical justification for beginning with the overture to Weber's Oberon - the composer himself conducted its premiere at Covent Garden in 1826 - but despite Bernard Haitink's customary baton- magic this made a muted and shaky impression. We were listening for the acoustics as much as for the quality of the playing, and got little joy from either.
The musicians - overflowing from the stage on to little side-platforms - seemed unsure of themselves. The sound was at once bright and boxy, and in any case bore no resemblance to what it will be like when the band is in its proper place below stairs.
We had - well, we absolutely had to have - Placido Domingo singing with Deborah Polaski in the ensuing duet from Die Walkure, but he was muted too. No fire, no sparks jumped between them as they sang at each other across the front of the crowded stage.
To round things off with the liberation scene from Fidelio may have seemed a pleasantly symbolic idea, but it proved a lead balloon. The Royal Opera Chorus sang bravely, Christine Brewer as Leonore hit the heights, but one never felt for a moment that this was more than a routine concert performance. With all the world watching - on BBC2 and live on the Internet - it was thoroughly perverse to settle for such drab ordinariness.
All of which leads to the conclusion that, while the Royal Ballet's troubles seem over, the Royal Opera's are deepening by the hour. Whose hand is on the tiller? Or is the ship floating free? It seemed odd to make Ligeti's opaque Le grand macabre and Birtwistle's rebarbative Gawain the second and third items in the new house's inaugural programme. These were part of outgoing opera director Nicholas Payne's strategy, and it should have been ripped up. Now we learn that the technologically over-ambitious Falstaff may hit the rocks. Oh dear.
Nostalgia: it's a great thing in the right circumstances, and the Royal Ballet's decision to take a look through its memories was exactly the right thing for the reopening of the Royal Opera House. Sentimental but proud. How clever, besides, to present these brief extracts from past highlights so simply and swiftly. One after another they came with no waiting for applause, so that finally it was the cumulative and collective effect that succeeded.
Not that the public fails to notice a star when it sees one; why else the tumultuous response to Sylvie Guillem as Manon dying so tragically? But Viviana Durante's Juliet did not go unremarked, nor Miyako Yoshida's quiet rapture in Symphonic Variations, Sarah Wildor's jollity in the cherry-eating duet from A Month in the Country and Darcey Bussell's smiling enjoyment of her role in The Prince of the Pagodas.
Yet for once, many of the peaks came from men. Do we miss that over-hyped group who defected last year? Definitely not, when Bruce Sansom remains to revitalise the real old Royal Ballet style, and is joined by Carlos Acosta swinging boldly and soaring through the Corsair solo, and Johan Kobborg crisp, neat and brilliant in a solo from Napoli. Angel Corella's debut in two numbers came as a foretaste of other male guests due here shortly - and don't write off Irek Mukhamedov yet, either.
Good to be reminded briefly of the company's past debt to visiting choreographers (Balanchine, Massine, Nijinska) and of Nureyev's enormous contribution to the Royal Ballet through his productions as well as his dancing. It was a great shame, though, to have two of the Royal Ballet's founders, Ninette De Valois and Robert Helpmann, represented only in photographs and to miss out entirely any hint of choreography by such greats as John Cranko and Antony Tudor.
Nevertheless, a vital aspect of the programme was that more than half the pieces given had been created over the years especially for the Royal Ballet. So this was not just nostalgia but a positive celebration of solid achievement. And more important than the refurbished auditorium (still, alas, with some interrupted sight lines) or backstage facilities, is the increased scope now available for continuing creativity. We know that all companies have problems in finding good choreographers, but if the new theatre helps overcome this, the gala could be a pointer to new as well as old achievements.