Youssou N'Dour, Barbican, London

The Dakar-born singer Youssou N'Dour is one of a generation of West African music stars who crossed their own native traditions with the music of the Caribbean as it returned to source in the first years of African independence. Later, the dominant templates of Western pop, rock and soul provided the fuel to forge their international reputations. Just as griot singer Mory Kante reached a new world audience with the dance-floor hit "Yeke Yeke" in the Eighties, so N'Dour went international via collaborations with Peter Gabriel and Paul Simon, and later with Neneh Cherry on 1994's huge hit "Seven Seconds".

Recently, however, the likes of Mory Kante, Kasse Mady, and Salif Keita have returned to the acoustic roots of their music, and with his new album Egypt, recorded in Cairo and Dakar in 1999 with the Fathy Salama Orchestra, but not released until this summer, Youssou N'Dour has crossed the Maghreb to combine the sounds and instruments of West and North Africa. The result has been hailed as a classic.

The album's live debut was at this year's Festival of Sacred Music in Fez, and though the Barbican may not be as thrilling a setting as Morocco's medieval second city, N'Dour's devotional music - the Senegalese title of the album is Sant Allah (Thanks God) - conjures a medina of the mind, in a seamless, 90-minute performance that expands and builds upon the songs from the album, and draws standing ovations from a packed house.

With Egypt, N'Dour leaves behind his Afro-Cuban mbalax (rhythm) music for a tapestry of sound that combines sweeping Arab melodies with pulsing, interweaving West African percussion. His voice, with its warm, intimate tones, its remarkable range and intense humanity, here becomes a vehicle of faith in a cycle of songs sung in his native Wolof that praise the mystical Sufi schools of Islam that have centred post-independence life in Senegal, in particular the religious leader Cheikh Ahmadou Bamba, founder of the Mouride faith that N'Dour follows, and a key figure in the country's early nationalist movement.

Tonight's performance is a previously uncharted synthesis of ethnic forms that creates a music that is innovative, thrilling and contemplative. Soaring strings sail upstream against a breeze of woodwind, oud, flute, balafon and kora, combining with a fiery panoply of Senegalese and Arabic percussion and the vocals of N'Dour and his chorus, to create powerful music that carries the audience far beyond the confines of the Barbican. It is a blending of musical cultures that proves to be a dazzling tour de force, and with some remarkable solos from percussionist Sitapha Mbaye, oud player Mamdouh El Gibally, and flautist Abdalla Helmy.

It is four years since N'Dour recorded Egypt, and much has changed in the world - for the worse - yet tonight's concert returns us forcefully to the unifying spirit of a music that ranks with the best in the world.