Nick Kyrgios sinks into the sofa at his rented home by Wimbledon Common, wearing his favoured off-duty kit of baggy shorts and basketball top, and is wondering how he ever came to be here.

'Growing up I never thought that I would be a professional tennis player, never crossed my mind,' admits the 23 year-old Australian. So you're the accidental tennis player? 'You could say that, yeah.'

Some days he is very happy in the role, other days he is not. This goes some way to explaining his unpredictable behaviour on court, about which he is disarmingly honest.

Nick Kyrgios admits some days he'd rather do anything else than play tennis

'I played eighteen tournaments and I probably tanked eight of them, but I'm still ranked in the top twenty,' he says, with a jaw dropping matter-of-factness.

Kyrgios defies simplistic analysis and divides opinion like no other player in the game. But on one thing everyone is agreed, including sages such as John McEnroe and Brad Gilbert: he has more raw talent than anybody tennis has seen since members of the 'Big Four' first emerged.

The invite to go round comes on Thursday afternoon. He is on his way back from practice at Queen's Club when I arrive, to be let in by his mother Nill who, it turns out, is absolutely charming.

Kyrgios will play at Queen's in London next week as he prepares for Wimbledon

Over a mug of tea she tells of how her younger son morphed from a tubby child into a pristine athlete; how she met his father George while they were students at Canberra's university; of overnight car journeys to country towns where they would stay at caravan parks while he played junior tournaments.

And also of the hurt she has sometimes felt at vehement criticisms of her son. She admits can be headstrong but feels he is undeserving of some of the more personal attacks.

After a while Kyrgios arrives back with a cheery 'Hello!' and a beaming, natural smile. It is a scene of normal domesticity miles removed from the portrait of him as some Prince of Darkness.

Andy Murray has become a good friend and is among those who have said that the latter image is way different to reality. It turns out they have just been in the gym together, where Murray has been winding him up about his basketball skills compared to those of his compatriot Bernard Tomic.

Kyrgios grew up in Canberra and he has always had a particularly strong personality

Growing up he admits he never thought he would become a professional tennis player

Eight-year-old Kyrgios (far right) with his dad George and team-mates after winning his first tennis trophy. He now has three ATP level tour titles

Kyrgios's mum, Nill, revealed how her son morphed from a a tubby child into a pristine athlete

SUPER STAT 2 - Nick Kyrgios is one of only two players, along with countryman Lleyton Hewitt, to have beaten Rafael Nadal, Novak Djokovic and Roger Federer at the first time of asking. Advertisement

The Scot and Kyrgios have much in common, from a not immediately obvious personal warmth, to a tendency to question received wisdom, to an uncanny tactical reading of the game. Murray knows what it is like to feel misunderstood while you make youthful mistakes very publicly.

What they do not share is an unabashed love of the sport and a meticulous attention to detailed preparation. And while Murray has learned to choose his words carefully, Kyrgios remains gloriously unfiltered.

'Some days it's fun to play but sometimes I'd rather be doing something else,' he bluntly concedes. 'When I'm on the road there are times when I find the motivation tough. I don't like the long trips, I dread them. I hate the travelling.'

At Queen's last year - where he is playing next week - the story went that, when his first round match against Milos Raonic was called, he was lying on a sofa in players' lounge. He then just picked up his racket bag and walked straight out on court without warming up. You ask if this is true.

'Yes, that's what happened. I just like to go out on court and play some tennis, although I don't think people believe me. I couldn't have the same approach as Raonic. He has a big team around him and does everything very diligently, that isn't me.'

At Queen's last year he didn't prepare for his match against Milos Raonic in the first round

He has, though, stepped up his level of professionalism since an early exit from January's Australian Open left him feeling 'in a dark place'. He has spent most of his career without a coach, but since then he has been doing some work with Frenchman and ex Wimbledon semi-finalist Sebastien Grosjean.

Kyrgios is again startlingly direct about their arrangement. 'I really like Seb, he is a caring guy who is helping me and we get along great. But I would rather not have a coach if I'm honest. I got sick of people around me saying I need a coach so I've got one. He's not too full on.'

Many believe that Kyrgios will win Wimbledon one day. He made the quarter finals aged 19, dramatically hitting Rafael Nadal off the Centre Court in the fourth round. His loose right arm can impart extraordinary power onto a tennis ball, and his astute reading of the game is underrated .

'I love it here in London, and I feel Wimbledon is probably my best chance of winning a Grand Slam,' he says.

While his talent is highly unusual, there is a contrasting ordinariness about him outside the pressure of the rectangle. He admits to doing foolish things in the past but explains that he struggles with the blowtorch of public scrutiny.

He says his approach to the way he plays tennis has changed, as has his attitude

'I hate people thinking I'm anything different to them. I just play tennis, I'm a normal young guy, I love spending time with my girlfriend (Croatian-Australian player Ajla Tomljanovic, whose name is tattooed on his wrist), I love basketball, I play video games. I'm not at all high maintenance away from the court.'

He also likes football, and as a Spurs fan is a big admirer of Harry Kane. But basketball is his major passion, particularly the Boston Celtics, and he played it to state level until choosing to concentrate on tennis.

'I sometimes wonder what would have happened if I'd stuck with basketball, but the path I've chosen is not the worst. I originally played tennis because my brother (Christos) was playing and my parents wanted me to, and I found it came pretty easily to me.'

He has clearly been blessed by coming from a strong and supportive family of three children (his sister Halie is a musical actress). Nill - short for Noralia -is originally from Malaysia and arrived in Australia aged twelve. A software writer, she met his father George, who still runs his own small painting business, through being in the same university class.

Kyrgios worked hard at his game and also to get himself in the best shape possible

There is no history of tennis in the genes but his mother was a national college badminton champion. His father had a season playing professional soccer in Melbourne and was offered terms to go and play back in Greece, where his family are originally from, but turned it down.

Nill, who has not spoken publicly before, describes how her younger son was initially unexceptional at tennis due to his build: 'He was a chubby little boy but always very strong and competitive. We knew that he would lose his puppy fat eventually because that was what happened with his older brother. He was also lucky in that there was a very strong group of boys his age in Canberra, and they all pushed each other. Quite a few went on to win tennis scholarships to colleges in the United States.'

By twelve Nick was starting to edge ahead of the pack and won a national title. His victory speech that day is fondly remembered in Canberra tennis circles. It amounted to: 'I would like to thank the canteen ladies for their delicious chicken sandwiches.'

He has built a reputation in the past for having a short temper which has got him into hot water

His childhood coach, Andrew Bulley – who still strings his rackets – recalls a boy never afraid to question what he was being taught: 'He was a very nice kid but he was not into repetition work and always wanted to know why we were doing a particular drill. If you didn't have a solid answer he would find you out. I think that's maybe why he has never been that keen on having a coach.'

By now his family were into a routine that other tennis parents will recognise, ferrying their offspring around and trying to meet the costs. 'We didn't have much money so we would stay in caravan parks during tournaments and sometimes you'd arrive there in the middle of the night, because we had to leave late after basketball practice,' says Nill. '

There are no lights on those country roads, you just hope that you don't break down. Nick would sleep on the back seat under a blanket but he never complained. Luckily, because I was writing computer software for hospital pharmacies, I was able to work on my laptop while he was playing.

'It was fine. Actually until recently we have never stayed in very smart places, always the same little hotel in Melbourne.'

The family have also lived in the same house in the north Canberra suburbs for 31 years.

She admits there have been times when the criticism of her son has got to her. Australian swimming legend Dawn Fraser was among those who piled in after his controversial exit at Wimbledon two years ago to Richard Gasquet, when he admittedly appeared to give up during one game.

Kyrgios grew up with 'a very strong group of boys his age in Canberra', says his mother Nill

'All children are different, young people aren't always angels, I'm sure Dawn Fraser wasn't an angel herself when she was younger,' responds Nill. 'I wanted to explain that they don't know him. At the beginning it hurt a lot but it doesn't register as much now. I've been called a bad parent. I've talked to Judy Murray about it, she has gone through the same thing. Nick actually cares about other people a lot.'

She also points out, along with others who are close to him such as his British manager John Morris, that the relationship with Tomljanovic has been a positive influence.

As a sport tennis is unsure about what it wants from Kyrgios. Desperate for new stars who generate interest as the stellar generation of Murray and co. get older, it craves his untamed, box office appeal. But then it cannot look the other way, such as when he tanked in Shanghai last October, which led to a suspension.

He is not a saint, but he is far from an irredeemable sinner. In the next few weeks it will be hard to avert the eyes from this most compelling, deceptively complex athlete.