OPERA Le Pescatrici, Cosi fan tutte Garsington, nr Oxford

If Monday's much-bruited wrecking attempts at Garsington proved anything, it was that, no matter how choosy you are about your repertoire - and this year's open-air season boasts two real rarities in Haydn's Le Pescatrici and Richard Strauss's Die Aegyptische Helena - you can't choose your neighbours. Leonard Ingrams, Garsington's opera-loving owner (and brother of Richard, ex-editor of Private Eye), may have armed himself with a seven-year permit to perform, but his neighbours are having none of it and fought back on opening night with an Ivesian medley of garden strimmers, overflying light aircraft and ringing car alarms. By Tuesday's second night, Spitfires had chased off the buzzing marauders, but hurricanoes struck, and crows and jays shrieked expletives more vindictive than their human counterparts.

Did it matter? Not when the battle of the sexes was being played out so artfully on stage. In a natty piece of programme planning, Garsington did what it does best: test-driving Haydn operas that rarely see the light of day, alongside Mozart done straight, unmarred by "inventive" distraction.

So it was women behaving badly, but chaps too. Set aside the surpassing poise and balances of Cosi fan tutte, this year's "find" was Haydn's "The Fisher Girls" (Le Pescatrici). Each is a comedy of errors: while in Cosi, Don Alfonso's choreographed duo woo each other's partners, in the Haydn, they woo their own. If Da Ponte's text is a springboard for leaps forward in social commentary and operatic form alike, Goldoni's is staple Plautine opera buffa, larded with double entendre of the kind Elizabethan audiences relished well before Enlightenment values got a formal look in.

Both operas - and pairs of lovers - flourished. Robert David MacDonald's Haydn was riddled with well honed detail: tightly controlled even in the most ludicrous exercises in piscatorial sexual innuendo. He was blessed, vocally and visually, in his ingenious pair of tenors, Jeffrey Lloyd-Roberts (last year's no less excellent Albert Herring) and Aled Hall. Memorable Haydn or no, mere unfamiliarity should not make us unduly unkind to an early Singspiel-burlesque that deserves some affection.

Next most satisfying feature was the chorus, admirably managed in both operas (director Ian Judge's languid tableaux and kindlily choreographed entries in Cosi not least), and delivered with a focus and commitment that uplifted at every turn. Haydn's women fared well, arguably better singly than paired, though twice hampered: an oversevere pruning of Lesbina's arias reduced Lynne Davies to too much of a cipher; and the crucial arias of Eurilda, the Perdita of this particular piece, who recovers her lost ancestry, are substantially lost. That Patricia Bardon had mislaid her voice too (her part sung capably by another, though like Garsington's capable Guildhall orchestra, too tucked under parapet for the audience upper rows) turned all but the comedy into mere mummery. Two snappy arias and one slow one (a curious Mozartian pre-echo) were helped by slick accompaniment under Wasfi Kani, just once (early in Act 2) unduly rushed. Paired cor anglais (Haydn) and solo horn and clarinets (Mozart) were pick of the obbligati.

From Tarantine frivolities to Ferrarese-cum-Neapolitan misdemeanours is an awesome leap. Garsington managed it admirably. To serve up a fine sextet (no weak link) for Cosi the next night was a palpable victory. Ian Judge kept his farce-propensities well leashed, and the old limp early move ceded to clarity, restraint and common sense. Cara O'Sullivan's devastated Fiordiligi won most hearts, secure on high notes (even when sung supine); when her resonance receded, just a smidgeon of flatness crept in too. Richard Halton's infuriated Guglielmo, American Jeffrey Lentz's anxious Ferrando, Janis Kelly's shrewd but winnable Dorabella and Andrew Slater's affable Don Alfonso, plus much more impeccably crisp ensemble, all iced the cake. But chief accolade perhaps to the Caballe pupil Silvia Tro Santafe, a remarkably strong and characterful mezzo-soprano find, and a triumph in her British debut as Despina.

'Le Pescatrici' in rep to 5 July. 'Cosi' in rep to 4 July. Strauss's 'Die Aegyptische Helena' opens 22 June. Booking: 01865 361636