John Etheridge, Pizza Express Jazz Club, London <!-- none onestar twostar threestar fourstar fivestar -->

John Etheridge's week-long residency at Pizza Express promised "exceptionally special guests" from the guitarist's extraordinarily varied career.

He started the week with a guest who certainly merited that billing, the classical guitarist John Williams. The contrasts between the two were many. Williams, quietly spoken, produced notes from his classical guitar that were oboe-like in sweetness and intensity. Etheridge was supremely laid-back, calling out to the audience for a file after he broke a nail, and cracking jokes about his sartorial deficiencies. But there was nothing lacking in his playing, in which his soaring improvisations were the perfect foil to Williams's more formal technique.

Both played solo numbers, Etheridge dipping into the standards with "God Bless the Child" and Sonny Rollins's "Doxy" and Williams demonstrating his mastery of the Latin American classical canon. Music from Mali and Senegal flowed from their fingers when they joined each other, but in their own compositions, the combination moved to another level.

Etheridge, who swapped between acoustic and electric guitars, laid down a series of arpeggios to introduce his "Strange Comforts", a tune that nicely unsettled the ear with its chord changes, and then let Williams take over harmonic duties, allowing him to solo more freely. They ended with a tour-de-force arrangement by Williams that pointed to the heights these two are likely to scale the longer they perform together; this was the first time they have paired up.

Now called "Extra Time", the number was originally titled "8-4-7" in reference to the first three chords in Bach's C Minor Prelude. The two guitarists worked their way through the prelude's form, gradually developing it into their own. The last quarter, where bass notes anchor what I've always thought of as a recitative section (what jazzmen might call "the stops"), became a series of mini-cadenzas for Etheridge, before both, remaining true to Bach, brought it crashing to its magnificent conclusion. The pair moved on, first to a lyrical passage, and then to a long ostinato section that mesmerised the listener as the two wound the tension ever higher.

No encore could quite follow such a finale. Anyway, as Williams explained, they had no more material: "That really is all we know," he apologised. They'll have more ready in time for a forthcoming US tour.