Their second programme together - in which the choreographer takes to the stage himself - has a format so simple it's old-fashioned. There's a solo for her, a solo for him, another solo for her, then a duet. No sets, no live music, no special effects other than lighting, yet the cumulative effect is as sophisticated as one could wish. This is intimate stuff, even in the vastness of Sadler's Wells, but it's meaty in impact. People were jammed shoulder-to-shoulder in the proms area, and all you could hear was a holding of breath.
The opening item, Solo, uses the recorded flamenco guitar of Carlos Montoya. But from the first sight of Guillem in a short red wig, pacing barefoot as the guitarist's fingers limber up, it's clear we're not to expect a flamenco response. Instead, Guillem winds her snaky torso round the music's figurations, lazily swinging out a hip or extending tendril arms. When the guitar reverts to strumming, she appears to forget to dance and ambles about the space, occasionally flicking a leg up to her ear as if to swat a bothersome fly. There's none of flamenco's eye-contact, none of its stamping, stand-off challenge. Solo merely leaves you dreaming of late siestas.
Shift, the 1996 solo taken by Maliphant, feels oriental. Modest in whites on a white-lit stage, he elegantly shifts and dips and shuffles, soft-limbed and gravity-bound. Then he's joined in his contemplations by life size shadow versions of himself: one, then two, then three. This clever trick opens up what might have been a too-small miniature into dazzling origami. The final solo, Two, finds Guillem trapped in a cube of bronze light. Like an animal in a cage, she repeats gestures with an intensity that soon becomes wild. Under Michael Hulls's chiaroscuro beam, only parts of arms or shoulders are visible. Gradually they become spits of flame, and by the climax Guillem's entire whirling limb span is one magnificent catherine wheel.
When Push - the newest work on the bill - finally brings the two artists together, the anticipation is electric. What will happen when the long, spun-glass body of one meets the padded compactness of the other? Will Guillem tower over Maliphant? Will there be a struggle? In the rapt opening moments it's clear the mood will be proud and sensuous, a meeting of strangers as equals. As Guillem crouches behind Maliphant's neck and slowly uncoils her body down the length of his back, and as Andy Cowton's delicate sound score hints at an ancient world, I suddenly see the pair as Helen of Troy and Paris. The image holds true as Maliphant cradles Guillem above his head, or catches her as she falls forward like a felled tree. This may be bold, new territory for dance, but the response it unlocks is rooted deep.