Major operatic careers have been kicked off when a little-known singer has deputised in a leading role. After the first night of Covent Garden's revival of La Traviata, one wonders what the future holds for the Lithuanian tenor Edgaras Montvidas. A member of the Royal Opera's Vilar Young Artists programme, Montvidas was pitched at short notice into taking over as Alfredo from the indisposed Roberto Aronica. He is a rather fine exponent of the role.

His voice, reedy and elegant, is on the small side, though he sings with an instinctive feel for the inner pulse of Verdi's music. He is a convincing actor, too, first approaching Violetta with a combination of gauche desire and the stiff-backed wariness of someone tentatively breaking away from the legacy of a morally rigid upbringing. When he publicly denounces her, he is ambivalent and wretched rather than blind with rage.

In fact, he is better than Violetta, the Albanian soprano Inva Mula. She can sing and act, though not always at the same time: she delivers the bulk of her vocal utterances straight to the audience, then follows them up with the requisite dramatic gesture aimed at whichever character she is with on stage. She abandons this habit when she gets to the final scenes, by which time one's sympathy is wearing thin. Her voice has a dramatic tang, though she is over-fond of hanging on to high notes, slowing the score whenever she does so.

Alfredo's father is played by the outstanding Paolo Gavanelli, who achieves tragic stature in his portrait of a man gradually realising that his severe codes of conduct have brought about nothing but destruction. The conductor is Paolo Carignani. When Mula stops faffing with the music, Carignani is wonderfully forthright, propelling the score forward with an immaculate judgment of its ebb and flow.

Daniel Dooner has revived Richard Eyre's production. He plays down the intimations of an abusive relationship between Alfredo and his father that made the original so telling, though he provides insights elsewhere. For instance, the Baron (Darren Jeffrey) is now young enough to be a credible sexual threat.

This Traviata is worth hearing for Gavanelli, Carignani and Montvidas. If Aronica is restored to health and you miss Montvidas, you can catch him in the same role with Glyndebourne Touring Opera next year.

· In rep until January 20. Box office: 020-7304 4000.