Abdullah Ibrahim, Royal Festival Hall

Not a word was spoken as a gracefully-greying Abdullah Ibrahim walked quietly on stage, made a gentle salaam-sign, and settled to play. With his percussionist George Gray lightly dusting the drum-kit, and bassist Belden Bullock plucking sotto voce, Ibrahim teased out of his Steinway a few meditative chords. If the ghost hovering in the air was that of Thelonius Monk, that was as it should be, since Monk was this South African maestro's formative influence - even more than his mentor, Duke Ellington - when he was cutting his teeth in Sixties New York. But that was during Abdullah Ibrahim's incarnation as Dollar (from Adolphus) Brand, before his conversion to Islam: twice exiled by his apartheid oppressors, and only able to return to his native Cape Town in 1990, he's had to follow a long and winding road.

It was clear from the start that here he was going for the slow burn. The two accompanists - Gray managing to get a cicada-sound out of two sticks held aloft in one hand - provided washes of background colour, over which Ibrahim, exuding Buddha-like calm, delivered his laconic musical utterances. Every so often we got the whiff of a standard, but always woven seamlessly into the unbroken stream of thought: every note was perfectly placed. It was a full 90 minutes before he turned up the heat, moving into anthem-mode with a mighty under-lying beat: this was the music with which his compatriots had expressed defiance during the apartheid years. The evening ended not in a burst of magnificence - moments of high excitement had come and gone like gusts of wind - but in a lyrical encore of perfect simplicity. Come back soon.

Two days later fado queen Mariza returned to the South Bank, but now it's the Festival Hall she fills, not the Purcell Room of yore: she's a superstar, and everything about her act is big, from the dress she wears, to the lighting effects, to the sea of instruments covering the stage. Those who had not seen her before clearly loved the little jokes, the snatches of autobiography, the carefully-managed moments of intimacy, as when she seductively placed one foot on a chair and exposed her stockinged leg. Those familiar with this act were more likely to groan - both the jokes and even the glimpse of stocking were the same as last year. She prowled the stage exuding her trademark mixture of coyness and menace, and she sang as wonderfully as ever - no question about her vocal artistry, as her new album Fado Curvo demonstrates - but the whole thing was hammed and utterly fake. She even managed to destroy - through instrumental tricksiness - that timeless classic "Barco Negro".

Then something magical happened: as an encore she threw away her microphone, came front of stage with the true fado combo of Portuguese and Spanish guitar, and belted out a song as they do in the clubs. Then a man walked out of the audience singing, followed by a middle-aged woman, their voices carrying superbly despite this hall's supposedly "dead" acoustic. The audience went wild: at last they had a whiff of something real. It was as though Mariza was acknowledging the bogusness of everything that had gone before. Will this talented girl get back on the rails? Or will she succumb to the fatal lure of "performance art", from which there is usually no return?

Over at the Barbican, guitarist Juan Martin reminded us of the power and beauty of flamenco pure and simple. No meretricious stage tricks, not a trace of hamming, just one long enthralling sequence of instrumental solos, songs, and dances by his brilliant little troupe. I had not heard male singer Chato Velez before, but I hope to soon again.

Last week I misattributed the Pygmy-Ligeti CD African Rhythms: apologies to Warner Classics, whose brainwave it was.