When Judith Weir’s adaptation of a 14th-century Chinese play was first performed it was hailed as one of the freshest and most tuneful contemporary operas for years. Nearly two decades on, it still seems a little miracle of music-theatre ingenuity. The original Yuan dynasty drama, blisteringly fast and funny in this fine Royal Academy of Music staging by Jo Davies, is wrapped inside a “real” 14th-century story that takes the same scenario into infinitely darker and deeper shades (especially in this production, which updates the costumes to present-day China).

Weir sets all of this to music that is pungent yet beautifully translucent, every word crystal-clear. Much of it is scored for deft little combinations of just three or four instruments, often underpinning not singing but rhythmic speech. And the “Chinese” sounds are wonderful, too: neither Eastern nor Western, but plucked from an imaginative world that alludes and hints without ever lapsing into pastiche.

Within Yannis Thavoris’s sparse yet evocative sets — translucent screens and calligraphic squiggles — the show is stunningly delivered by students who seem not only to understand the hybrid medium but to revel in its startling changes of tone — from pathos to irony to slapstick, sometimes all in the course of a single sentence. If the casts of major opera houses acted with half the panache of the three singers who present the Chinese opera “proper” — Kishani Jayasinghe, Catherine Hopper, Allan Clayton — my life would be much improved.

The baritone Ronan Collett, whose voice seems richer and warmer each time I hear it, is outstanding as the anguished canal-building hero Chao Lin. And the Royal Academy Sinfonia offers a very spruce account of the score under Dominic Wheeler’s direction. Further performances until Monday.

There are also at least three good reasons for attending another student opera in London this week — Falstaff at the Guildhall School of Music and Drama. The first is Olivia Fuchs’s delightful production, set in a swanky 1920s country-club (Sir John gets dunked in the swimming-pool), and crackling with pace and energy. Much the same could be said of Paolo Olmi’s conducting, at least until a safety-first final fugue. There was a fizz and deftness about the orchestral playing, even if one or two big ensembles became slightly unhinged in the vocal department.

And the third reason to see the show is David Stout’s Falstaff, a remarkably nuanced, crisply sung and funny but never coarse portrayal of the old rogue from a singer who is surely on the verge of a considerable career. Last performance tonight.