Imagine you have to, or rather want to make a biographical documentary. You have at your disposal 500 hours' worth of footage, from which to obtain two hours for the big screen. And on top of that, the person you're dealing with is a sort of modern divinity, the secular patron saint of a city, one third of a sporting trinity. And you realize he's actually two different people: Diego and Maradona. All clear? Good, now you can understand Asif Kapadia's undertaking.
Interview by Boris Sollazzo