Adriana Lecouvreur/La Rondine, Holland Park, London

Kicked off this summer by The Pearl Fishers, director Matt Lane's spare, intelligent production of Suor Angelica, and Jamie Hayes's ebullient Pagliacci (with Geraint Dodd as a vocally awesome and vicious Canio), Opera Holland Park seems in remarkably buoyant form.

This year's plum is Francesco Ciléa's Adriana Lecouvreur. Director Tom Hawkes and designer Peter Rice are one of the best teams in the business. In 1998, they promoted L'Arlesiana, an even rarer opera by Puccini's verismo contemporary Ciléa (1866-1950). If Lecouvreur – premiered in Milan in 1902, launching Caruso as the martially amorous Count of Saxony – needs justification, it received it amply here.

What Hawkes and Rice put on stage is a delight to gaze on; each shrewd blocking and subtle vignette folds gracefully into the next. The effect might be sugary, but here it works gloriously. The set, a shifting sequence of tempting pastels, restores the Fragonard look that this attractive, 1920s rejig risked losing. Lecouvreur is the famous classical actress, admired by Voltaire: the cast's bustling, buzzing opening sequence is like Moulin Rouge meets La Cage aux Folles. Stage levels, props (none wasted, as when Justin Lavender's occasionally incongruous Maurizio leaps astride a circular blue sofa to expound his Saranoff-like military exploits), an exquisite Judgment of Paris dance sequence – all serve the story and Ciléa's score well.

Christine Bunning – more Mrs Thatcher than the Sarah Bernhardt figure hankered after by her adoring manager (Charles Johnston's admirably hesitant Michonnet) – had a moving shot at Adriana. Her top notes just lost it early on, but she has presence, and by the death scene it was all there. Lavender's antihero looks like a bellboy on first entry; he tends to welly out his fine tenor, which is fine for Maritana, but not for here. As the Princess who despatches her rival with a bowl of poisoned violets, Rosalind Plowright – a stage legend, having outfaced Janet Baker in Maria Stuarda – looks a killer from the start and sings to kill for, too.

Cutting in delivery, caked in sly irony, and abetted by Arturo Colautti's nicely snide libretto, John Gibbons drew much delicious playing from the mere 21 strings (plus harp) of an on-form RPO – the bassoons and flutes get my accolade. Lara Taylor's cor anglais nursed out the wheedling poison motif perfectly.

Nik Ashton's staging of Puccini's La Rondine is also a rarity, pace Covent Garden's recent Gheorghiu-Alagna triumph. It could learn a few tricks from Hawkes, and a woollier RPO lacked fire for the opening acts. But everyone, including the slightly muddying conductor Jeremy Silver, came good in Act III. The story (kept woman abandons new-found love to preserve his propriety) is touching, and the singing was grand. Anne Sophie Duprels was a ringingly warm Magda, if outdone by Gail Pearson's chirpy, Despina-like maid, Lisette.

Best of all were the two tenors: Dominic Natoli made an ably engaging Prunier, and the young Irishman Séan Ruane's natural movements and pliant, reined-in voice marked him out as one of the finds of the year.

To 27 July; festival continues to 10 August (020-7602 7856)