Mikhail Baryshnikov, Barbican, London

Been away so long he hardly knows the place...

As Carrie's new love interest in Sex and the City, Mikhail Baryshnikov plays a successful ex-pat painter, complete with smart apartment and beautiful friends. Presumably the producers didn't think it sufficiently credible that the 56-year-old (a grandfather, no less) could play a dancer. Dancers might be glamorous but they're not that old.

I don't think for a minute that the purpose of Baryshnikov's current solo tour is to prove them wrong. Still less is it a hankering for limelight. He made it clear he'd had enough of that a decade ago when he submerged himself in the ranks of his post-modern White Oak project. If the solo tour has an agenda at all, it's to show audiences what dance can be beyond the speed and elevation commonly thought of as technique. For technique was what we were seeing on that bare Barbican stage - pure technique, laser-powered focus, and an authority that only comes with years.

Divided into contrasting halves, serious and fun, the programme is carefully tailored to eke out Baryshnikov's stamina. Solo piano turns by Pedja Muzijevic allow him the occasional breather while the pianist offers up nuggets of coolly played Scarlatti, Debussy or Schoenberg, which also serve to alert the senses to detail. The alternating piano/dance combo is slightly quaint, recalling a style of concert that was common 70 years ago. But there's nothing quaint about Baryshnikov's passion and attack. The body is fit and taut as a bowstring. It can still do anything he wants.

Too bad the choreography he commissioned hasn't more meat on it. The opener, Cesc Gelabert's In a Landscape (to surprisingly romantic John Cage), is a formal study of contrasts, curves levelling into lines, lyrical phrases answered by weighted thuds. Simply and impeccably delivered, it is nonetheless remote and unenlightening.

Things look livelier in Tere O'Connor's Indoor Man, in which the dancer comes on with his top half surreally encased in a cardboard sitting room equipped with working wall lamps. Much of what follows draws on Baryshnikov's considerable talent for mime - honed for three decades on 19th-century ballet classics - as he fiddles with switches, examines his face for signs of wear in an imaginary mirror, and generally busies himself with the digital flummery that fills the hours of modern leisure. O'Connor could have pushed it one step further into anthropological comment, but it remains a one-trick joke, an entertainment.

Only Lucinda Childs's Opus One poses this dancer any real physical challenge, setting long, surprisingly classical phrases over the fingery clumps of Berg's Piano Sonata, and harking back to the star's virtuoso past in great loops of fast spins and attitude turns. The defiantly small, tight red trunks the dancer chooses to wear for this piece are unnecessary to prove he's a match for it. The beauty of classical style is all there under his skin. His port de bras, so gently and precisely held, is still exquisite.

The evening's second half plays up to Baryshnikov the showman, particularly in Eliot Feld's Mr XYZ, which pitches the dancer into the skin of a man 20 years older, chaining him to an office chair to the bluesy croak of Leon Redbone singing "I Ain't Got Nobody". You could read it as the ultimate act of self-effacement: the ageing dancer choosing to age himself further, mocking his own demise. But the bodily transformation from hard, thrusting spitfire to rumpled, baggy old man is so profound and startling that it becomes another kind of virtuosity, one more brilliant string to an already full bow.

I admit I blenched when Baryshnikov picked up a walking cane. That cute old vaudeville reference is so overplayed. But Mr XYZ redeems itself with humour (the old codger revving his castors to get at the girls), with elegance (partnering a tailor's dummy) and with sly references to Baryshnikov's glorious past. The whirring arms of Apollo, the strewn lilies from Giselle, trigger a lifetime of memories to the ballet faithful.

But ultimately, to its credit, the show resists nostalgia, because Baryshnikov wants to be part of the here and now. Hence the inclusion of a piece by Michael Clark performed with Michael Clark. The only time we see the older man break into a spontaneous grin is when he launches into a wild, limb-flinging romp alongside Clark and his company. Clark was the ballet prodigy who didn't choose to make it. Baryshnikov was the prodigy who did. To see them even briefly on stage together, thrashing away to the Beatles's "Back in the USSR", is a little piece of dance history to treasure.

jenny.gilbert@independent.co.uk

'Solos With Piano or Not...': Barbican, London EC2 (0845 120 7511), tonight