La Gioconda, unknown to most of us except as provider of the big tune for shimmying hippos in Walt Disney's Fantasia, is a work of extreme emotion and many exclamation marks.

"Suicidio!" sings the soprano. "Orribile!" responds the bass. "Orror!!" laments the mezzo. "Ho! he! ho! he!" chants the chorus of rollicking sailors. "High class tosh!" sniggers the critic, while lapping it all up.

Opera Holland Park began its illustrious history with another Italian rarity, Mascagni's Iris, in which the heroine throws herself in a sewer. In La Gioconda - the joyful girl - the blind mother is tossed into a Venetian canal and La Gioconda, now less cheerful owing to failed love interest, stabs herself.

After a slow start, this mad melodrama exploded into epic, grisly life and proved its worth. Written by Puccini's one-time teacher, Ponchielli, it's a reworking of Victor Hugo complete with poison, mixed identity, a witch, jealousy, adultery, the kitchen sink and an entirely superfluous ballet: the Dance of the Hours (Hello Muddah, Hello Fuddah). The score demands an organ, a bombardone - a kind of extinct bass tuba - double harps and onstage bands.

The City of London Sinfonia, conducted by Peter Robinson, played with distinction and fire. Gweneth-Ann Jeffers, forceful in the title role, led a hot-blooded cast in which Olafur Sigurdarson and David Soar were especially earcatching. The Russian tenor Vadim Zaplechny remained wonderfully Russian.

Martin Lloyd-Evans's production, with designs by Jamie Vartan, was modest. Ruskin would have swooned in horror at his beloved stones of Venice represented by breeze block but the pulley-assisted gondola was a bonus.

This is now the puzzle about Opera Holland Park. The small team running it has flair and ambition, explores unexpected repertoire and nurtures musicians of ever higher quality. When will the super rich Borough of Kensington and Chelsea support its enterprise with proper financing instead of basking in reflected glory?

• Until 9 August (0845 230 9769).