MUHAMMAD Ali is a certainty.

Tiger Woods, someday, maybe. Michael Jordan, a definite contender. Talking to director Asif Kapadia about sporting greats whose lives merit a big screen documentary, it soon becomes clear this is a club so elite it could hold its AGM in a Mini.

Sure of a place is the three times Formula One world champion who is the subject of Kapadia’s new documentary, Senna. Detailing the last decade of the Brazilian’s life before his fatal crash at Imola in 1994, Kapadia’s film aims to do for motor racing what When We Were Kings, Leon Gast’s 1996, Oscar-winning look at the Rumble in the Jungle between Ali and Foreman, did for boxing.

“He was a real superstar,” says Kapadia of Ayrton Senna, who was 34 when he died. Despite that fame, this is the first documentary feature film about his life, an achievement made possible by Senna’s family giving their permission, and Bernie Ecclestone opening the vaults of the F1 archive at Biggin Hill.

It was this access to footage of the time, and much else besides, that proved to be the making of Senna. Another director might have gone the conventional route of allowing “talking head” interviewees to tell the story and inserting footage around them. Kapadia reversed that, made the footage king and put contributors on voiceover. The result gives the film immediacy and freshness. Crucially, says Kapadia, it allows Senna to be the narrator of his own life. This is the man in his own words, with his own actions plain to see.

Getting through the footage proved a Herculean haul. Kapadia spent five years on the film, three of them in the editing suite. “You’d open one door and there would be 10 more,” says the 39-year-old Londoner. Nothing could be left to chance. An interview with Senna in Portuguese, once translated, turned out to be a rare instance of his talking about his spiritual side.

As Kapadia picked his way through the footage he had to work as much like a historian as a documentary maker. Everyone has their own memory of the times, he says. “It happened with all of our interviews. People will tell you a story but it doesn’t add up, it doesn’t match what I’m seeing. We had to meet everyone, cross reference our stories, then let the images tell the story.”

A key part of the Senna story was his rivalry with Alain Prost, the cool, calculating “Professor” to Senna’s daredevil. Talking to Prost in Paris was fascinating, says Kapadia.

“It’s difficult because you’re going to Paris to meet the four times world champion to make a film about the three times world champion. It must be strange for him. But we had to do it, and it was amazing. My feeling is that rivalry never really ended, there’s still something going on. People have not really dealt with it. He wanted to speak. He had a lot to say.”

Kapadia also spoke to Senna’s family at length. After that, they left him to get on with it. Cut to several years later and the family had travelled from their home in Sao Paulo to the Monaco Grand Prix, where Senna’s nephew Bruno was racing. With Kapadia in Cannes, this was his first chance to show them the film.

“We hired a cinema and there were 15, 20 family members and us. It was quite unbearable, the most difficult and emotional screening we’d ever had. Even when he’s winning and when people normally would be laughing you could sense there were sobs in the room. There were a lot of tears at the ending.”

After the credits had finished, Viviana, Ayrton’s sister, hugged the filmmakers and said they had managed to strike the perfect balance between the champion on the track and the man off it. “She said, ‘You’ve got it, you’ve done it’. It was a huge weight off our shoulders.”

Kapadia was new to documentaries, having been previously known for The Warrior, a drama shot in Rajasthan and the Himalayas, and Far North, an Arctic-set thriller. Something of an outsider himself – he was the first in his family to go into films – Kapadia is known for making movies about those who find themselves strangers in strange lands. Senna, who came from a wealthy background, wasn’t the most obvious outsider, but the more Kapadia found out about him the more he fitted the rebel mould.

“Right from the beginning he feels he’s taking on the best drivers, the Frenchmen, in Monaco, in a sport run by the French. There just seemed to be something with him and the authorities. He was always the one that would argue with them in drivers’ briefings, not always for himself but for safety for others.”

Then there was the other side. “He would be arguing for other people but then on the track he was a tough guy, saying if you don’t get out my way we’re going to crash.”

Though he was new to documentaries, Kapadia stayed true to what he already knew about making films, foremost among which was allowing the story to tell itself through choosing the right visuals, shrewd editing, and finding the right music. Some things still blind-sided him, though, such as the day he was going through the footage of Senna’s funeral, deciding what to put in and what to leave out.

“I’d never been in that situation before. It was very difficult.” Reality proving too much for the moment, he went out for a break. The London Film Festival was on, and he happened to see a drama that featured characters grieving over a loved one.

“I remember thinking, I’m not believing anything in this sequence. Everyone around me was loving it and I just thought it was all over the top. In reality, people are just numb, totally in shock. It makes me watch fiction films now in a very different way.”

Kapadia hopes to carry on doing both documentaries and features. Unlike Senna, who was go-karting almost as soon as he could reach the pedals, Kapadia only found his dream job the relatively ancient age of 17 after getting a job as a runner.

“I had to carry metal boxes in and out of the rain. For some reason I loved it. I thought it was the most exciting thing ever in the universe. It’s a bit like Formula One. I joined the circus and I never left.”

Back to talk of sporting greats. In Senna’s case, agrees Kapadia, it’s the blend of passion and skill, and the significance of his life beyond sport (which lives on in Ayrton Senna Institute, the charitable foundation established after his death to provide educational chances to deprived children) that makes him such a rich subject.

Says Kapadia: “He’s a complex character. Very driven, had to win. He was not only competitive with others, the guy was competitive with himself. There would be many a time when he would already be on pole position, the fastest guy by a long margin, and he would still go out and beat himself. The biggest challenge was always against himself.”

Senna opens in cinemas tomorrow.