Nuevo Ballet Espanol, Sadler's Wells, London<br/>Eva Yerbabuena, Sadler's Wells, London

Innovation is the watchword of the annual flamenco festival at Sadler's Wells. This year's line-up is dominated by strong women, with shows from Eva Yerbabuena, Rafaela Carrasco and Maria Pages, any of whom could have kicked off the season in style.

So it was quirky, if not perverse, to open the fortnight with an oddball male duo. Granted, in Spain, Angel Rojas and Carlos Rodriguez have garnered armfuls of prizes between them, but that's no guarantee of production values. Their latest show with their troupe, Nuevo Ballet Espanol, is a rum affair, determined, it would seem, to remind us of flamenco's low point in the Seventies and Eighties when it was reduced to a trashy holiday package.

If that sounds harsh, consider the evidence. The music is led by two husky females who belt out numbers in an unmodulated fortissimo, the flamenco equivalent of Essex-girl karaoke. (I could take only so much before blocking my ears.) The corps de ballet's wardrobe includes lusty black bras, while the male stars don a range of ill-advised get-ups: now leather gaucho aprons, now girly spotted shirts, now exaggerated high-waist trews that ought to elongate their line, but rather suggest they should go easy on the chorizo.

The show is titled Cambio de Tercio, a bullfighting term denoting change of direction. There are plenty of these in the course of this choppy display, as one sequence stops and another begins, with little notion of dramatic context, only an awful lot of costume changes. And was Angel Rojas being ironic when he stalked, glowering, across the width of the stage dragging a chair as if it were a dead bull-calf? I'd like to believe so, but I fear not.

In a mercifully short evening, there were a few memorable things. The singers turn in a catchy flamenco rap, yattering in unison at the men like demented fishwives. Rodriguez proves a likeable dancer, more supple and expansive than Rojas, whose stiff introspection comes across as preening vanity. Most off-putting, though, is the way the entire company begs obviously for applause, an old-school trait I hoped I'd seen the last of. If this is innovation, then I'm a Spanish aunt.

The last time Eva Yerbabuena appeared at Sadler's Wells, in the festival of 2005, she was "exploring the emotions and growth of the female psyche". Providing you ignore the similar guff that furnishes her latest offering Lluvia (Rain – "an element that reflects who I really am"), you are in for a rare and engrossing treat.

Flamenco – at least the sort that finds its way into big theatres – too often feels the need to present itself in garish colours. Melancholy also has a place in the palette, but only an artist of the calibre of Yerbabuena has the subtlety to exploit it, and still hold a large audience rapt.

Despite, or perhaps because of her short stature (and she's no waif, either), Yerbabuena has developed a fearsomely clean-lined style. Where on previous visits you might have likened her to a purring cat, all rounded, soft and enveloping, you would now put her down as a cobra, swift in attack and with a merciless edge.

Supported by the fine musicianship of her husband, Paco Jarana, and a singer with a voice like buckets of stones being dragged up a hill, Yerbabuena proves the truism that the only worthwhile innovation is that which keeps faith with tradition. Not all her novel devices quite come off, but at the heart of her performance is a fierce, dark rigour that accumulates a thrilling power.

Festival continues at Sadler's Wells to 27 Feb (0844 412 4300)

Next week

Jenny Gilbert weighs up the Royal Ballet's bid to find dance-making talent from within