You can tell a lot about a champion by the friends he has and the people he employs. As a tennis player, Roger Federer is imperious, his superiority manifest. Ask Lleyton Hewitt, who is the No 2-ranked player in the world but cannot find a way to take a set off Federer. He has lost 15 in a row.

Federer never brags. He just knows he’s a class apart. When, for a trivial example, he takes his purple towel from his chair to the back of the court, he sweeps it across his shoulder as if he’s a Roman senator adjusting his toga, about to deliver an oration. It is sure to be acclaimed.

Yet Federer needs no fawning entourage. In private and in his professional life away from the arena, he is quiet and normal. When he first won the singles title in 2003, he stayed in a rented apartment in Wimbledon Village. His girlfriend, Mirka Vavrinec, bought the groceries, cooked, washed up and did the washing and ironing. Two years on in their adventure, Federer is among the world’s leading sportsmen and a multi-millionaire. The house he has rented this time is rather grander and closer to the All England Club, and Mirka spends much more time fielding requests for Federer’s time and presence.

But does she still shop, cook and wash? “Yes, of course,” she said. “We’re just the same.” But why not use the official laundry service? “I like to use a particular washing powder.”

There is more than a nice-guy-at-home point in this. Most sporting champions whose careers are long and fulfilled are supported by stable private lives and a firm attachment between their feet and the ground. And if Federer’s career is to be so fruitful that the question of whether he might be the best player of them all becomes an aggregate of titles rather than opinion, he must remain as ordinary as possible.

The possibilities are breathtaking. Pancho Segura, who at 84 has progressed in status from master coach (having helped four Wimbledon singles winners) to oracle, put it thus: “Federer is the only complete player in the world. All the others are one-dimensional. Already he is one of the greats, and his potential is unlimited.”

Reaching that potential involves a law of inverse proportion: the more exciting and romantic the challenge, the more mundane and practical must be the approach. When Everest is the destination, you pack carefully and take everything you might need.

Federer’s expedition should interest every tennis coach in the world, and more than a few have applied to join him. Yet he spent every effort in persuading just about the most reluctant traveller, Tony Roche. What’s more, when you watch them working on court, Roche does not appear to be coaching. He hits, collects balls, offers the odd comment. But that is what Federer wants: the eye and calm judgment of a man who has been in top-class tennis for close to half a century.

In 1962, when Roche was an emerging player at 16 — Andy Murray, take note — he played Rod Laver in the Victorian state championships. Laver won all four Grand Slam titles that year, yet Roche served for the match. “ ‘Rocket’ broke my service and went on to win,” Roche recalled. “And the next time I played him was five years later, in the Wimbledon final.”

Roche won the French Open singles and five Wimbledon doubles titles with John Newcombe. Later, he captained Australia’s Davis Cup team and coached Ivan Lendl and Pat Rafter. Roche has no need to prove himself, and when he has nothing important to say, he generally says nothing. “A lot of people say, ‘How can you coach him when he’s so good?’ ” Roche said. “To me, it’s just little things. I don’t tamper too much.“

Last season Federer played without a coach. He won 11 titles, including three of the Grand Slam tournaments. Perhaps he did not need a coach. Federer insisted that in time, he would. Roche agreed to help him on a limited basis, to begin at the Masters Cup in Houston last November. “But I said to Tony, ‘Shouldn’t we catch up before that, to see if we match up and like each other?’ ” Federer said. “It was very important for me to get to know the human Tony.”

They met in Dubai in October 2004 and worked out for four days in scorching heat. “Then I asked Tony about our plans for next year, if everything was all right. And he said he didn’t think he could do it. He felt tired and hated the travelling and couldn’t do it properly. I told him it didn’t matter, that I hadn’t expected him to hit with me for four days, and I was amazed by how well he did.”

Roche, true to type, told it straight. “The physical demands were a problem,” he recalled. “I’m a coach who likes to work and hit on court. Not to be on the sidelines. You get a better feel for how your player is hitting the ball. I just found, turning 60, it was too much, even with Roger hitting straight back to me. I was worried whether I would be able to do that with Roger, at a good level.”

But Federer had already grown to admire Roche. “I decided to go to work with Tony for two weeks in December, before the season started. It was a huge effort for me to fly to Sydney, because I usually stay at home in December. Then, towards the end of all the sessions, my fitness trainer told me that Tony might be able to do a few weeks during the year. I asked Tony and he said, yeah, he could do a few weeks. That was amazing. I could hardly believe it. Two weeks was okay for me, anything was okay. He was all relaxed, saying, ‘Come to the Aussie Open and we’ll take it from there’.”

Federer’s excitement, which is still evident as he relates the story, betrays his affection for Roche. “I consider him my coach now, not my part-time coach. He was supposed to travel with me just up to the French Open, but then he said he could stay on longer, which is great.”

The arrangement could hardly be more casual. Roche can stay as long as he likes, leave whenever he wants. He is paid by the week. “Friendship is what’s important above everything else,” he said. “Ivan and Pat were the same. I’ve been lucky to work with three great players who are all great blokes. I’ve never had a contract with any of them because a shake of the hand is enough. If there’s a problem, we sit down and talk about it.”

It’s all amicable, but the task is serious. Federer may be the best by a street, but he must get better. “He works like Lendl,” Roche said. “Ivan was No 1 for so many consecutive weeks (157 in the mid-1980s), yet every day he got up, he felt he could be a better player and would work for that. With Roger, it’s the same. He’s dominating, but that’s no reason to stop there. The others are working hard to catch up with him, and that means he must improve. And there are areas where he can.

“We all know that he’s already in the company of the greatest of all time, and he reminds me a lot of Laver. He has that versatility. He can adapt to all surfaces and opponents, and has so many options. That is unique in today’s game, because the others are one- dimensional.

“And there’s another way in which I think he’s unique today. It’s the respect he has for the game. He loves to hear about the past, about Laver and Rosewall and the rest. And he cares about the future. The reason he plays is he loves it.”