It was the rats that most traumatised Mesut Ozil. Almost everything else about his childhood growing up in Bulmke Hullen, a mini Turkish enclave in the German city of Gelsenkirchen, seems to have been generally positive.

The fourth-floor apartment his family lived in was small and he shared a room with his brother, Mutlu. As the older brother, Mutlu got the bed and Mesut just a mattress, which was stored away during the day. He lived a parallel life to most Germans, speaking only Turkish until he was four.

But despite the relative poverty — his mother was a cleaner and his father a factory worker — it seems he was happy with his lot. But not the rats in the cellar.

Arsenal star Mesut Ozil has opened up in a rare and revealing interview to Sportsmail

The cellar to the apartment block had to be negotiated if you wanted to fetch your bike. And that was not a job to be undertaken alone. The children would only approach that task in groups.

'It was like that at the time,' says Ozil. 'I was pretty small. I was always the youngest in our group, too. When you went into the cellar, there wasn't an on-off button for the light. You pressed the button and 30 seconds later the light would go off again.

'You wouldn't know where things were because it was so dark. Sometimes you'd hear the noises. When you see such a big rat in front of you, it would freak you out. I always went down with others; never on my own.'

He smiles at the memory, happy to recall his childhood, proud of what he has achieved. Rats pose no dangers now.

Ozil is something of an enigma, not just on the pitch. He rarely gives interviews. He conducts this one in German, though his English is good. Until now, a full picture of him has been hard to visualise.

Now his autobiography is being published in England, it is possible to piece together a portrait of the footballer who is supremely talented; infuriatingly so at times.

The German star is adamant that he wants Arsene Wenger to stay in charge at Arsenal

In conversation he is reflective, forceful and measured. He knows that his life story has wider significance beyond football and the account of his childhood is one of emotional wellbeing amid material hardship.

'For us it wasn't important to have a big house, a few cars, always have the newest clothes,' he says. 'Solidarity as a family was important. We were there for each other and always will be.

'There were days you'd want to buy certain things or afford things and didn't have the money, but what was most important was to spend time with each other, to grow up together.'

And yet amid the benign memories, there are also more sinister overtones. One chapter of the book recounts how several Bundesliga clubs turned him down as a child, including, initially, his local team, Schalke, despite his ability.

Boys of lesser ability with Germanic roots seemed to be preferred; German boys with Turkish roots, less so.

Ozil finds the back of the net during Arsenal's 3-0 win over West Ham at the Emirates Stadium

The German celebrates in trademark fashion after scoring his 10th goal of the season

'The older you become, the more you understand it,' he says. 'As a kid, you'd go to have a trial at a big club.

'You'd be the best and there'd be a big difference between you and next person. You'd think they'll 100 per cent take you but then they'd say: "We'd rather have him. You have to wait a week".

'I'd go somewhere else for a trial and have the same, where I was the best. When you've experienced that three or four times, you notice it. I'd say: "Dad, why?" He'd say: "Mesut, it's not down to you, it's down to your background, because you're Turkish and because you're called Mesut". At that time, it was much more extreme. I don't know what it's like today but at the time it was very difficult as a kid.'

You can sense those experiences hurt. It was Ozil's grandparents, miners from Zonguldak, who answered the call from West Germany in the Sixties when the nascent state needed fresh labour for the Ruhr coalfields.

His parents were born in Germany, as was he. 'When I look into the future and where I'd like to live, I'll say Germany because I grew up there and like the discipline the people have,' he says. 'But my background is from Zonguldak in Turkey. I'm there a lot.'

Ozil pictured in action as the Gunners returned to winning ways over West Ham last week

The barriers which he had to overcome add context to his personality. The puzzle about Ozil is that he is in one sense a genuine footballing superstar with an even more compelling back story than, for example, Lionel Messi or Cristiano Ronaldo.

He is a German phenomenon, the national team player of the year for five of the last six years. These are the world champions and he played his full role in winning that trophy in 2014.

He is the man courted by Chancellor Angela Merkel as a role model for integration in a modern Germany. On the flip side, he is the man far-right politicians called 'anti-patriotic' when he posted pictures of himself at Mecca.

'The hype is big, regardless of what I do,' he says. 'As a Muslim, you have to go there (Mecca), see it and experience it. It was a great experience for me. I'd like to do it again. I wanted to post about it because lots of fans had asked. I didn't do it to provoke anyone. It's what I believe in and I stand by it.'

He has become a totemic figure, so his contribution to the World Cup win was cited as an example of how integration succeeds. Perhaps, naturally, he balks at the role some would thrust on him.

The 28-year-old poses with the World Cup trophy after Germany's win over Argentina in 2014

'It's not my task,' he says. 'Every person needs to try to integrate and I think the best example is the German national team.

'When you look at the team, you see lots of players from different countries. Jerome Boateng has a Ghanaian background, Sami Khedira, from Tunisia, then me, too. What's most important is that we respect one another and understand each other.'

He does acknowledge he is a global role model but with one important clarification. 'Not just for Muslims,' he says.

'I'm a role model as a footballer and not as a politician. I want to see myself as a footballer. People respect me for my performances. That's why they support me and I'm very thankful for that. But I'm not a politician.

As such, he transcends cultures. And his football ability is not in doubt, nor his achievements. However, he is also aware, of the counter-narrative he attracts: that he should rise to still greater heights, perform better, win more.

It fits with Arsenal's own situation: the sum of the team being less than its parts. He discusses the whole issue of not performing in the big games, the criticism most frequently thrown at Ozil.

'I hear a lot, but I don't give any worth to it,' he says. 'What the manager says is what's important to me. What experts say doesn't interest me and never will. I know what I can do. I've not been playing at the top level for nothing. I've been successful.'

He is of course a World Cup winner, a winner of La Liga and La Copa del Rey with Real Madrid, the German Cup with Werder Bremen and the FA Cup twice with Arsenal.

Ozil scored a stunning hat-trick during Arsenal's 3-2 Champions League win over Ludogorets

And no one could sensibly argue Ozil is bad or hasn't achieved. The argument is more that he isn't Messi or Ronaldo. He is more creator than scorer, of course, playing a deeper role. Assists are his thing.

'The expectations are very high, as mine are for myself too. I have big expectations of myself,' he says.

The point about Ozil is that he surely ought to be challenging to be FIFA World Player of the Year awards.

'To do that, you have to win the Champions League, otherwise it's very hard,' he counters.

'I think every player wants to win that award but it's not my goal. If it happens in my career, that will be nice, but for me titles with clubs are more important.'

Although his personal trophy count is impressive, Arsenal's isn't of late. Significantly, the two FA Cups they have won came after Ozil arrived.

But the Premier League title they surely should have won last season, once they had hauled Leicester back to within two points in February, now looks a distant proposition.

When they beat Leicester last year to bring them back to within touching distance, Arsenal then subsequently lost to Barcelona (twice), Manchester United, Swansea and Watford in a seven-match run.

Ozil and team-mate Lukas Podolski celebrate their FA Cup triumph over Hull in 2014

When that flaw is put to Ozil, he seems to suggest the team ponder their setbacks too much.

'Sometimes things don't work as well in games as they have in previous games. If you lose, or you give a goal away or don't make an assist, you can't think about it too much, can't dwell on it.

'We need to realise as a team that if things don't go for us, if we lose, we need to not dwell on it and focus on the next game. Sometimes you have the feeling when we lose, some players may lose self-confidence.'

Is it a collective mental problem with the team?

'You'd have to ask the manager. When I look at the team, the players are ambitious enough and want to be successful.

'But sometimes you can't implement that in games where opposition dominate and we think, "They are stronger than us". Even when that is the case, we need to battle until the last second. If you believe in yourselves, you can achieve a lot.'

Ozil admits that Arsene Wenger was a main factor in him joining Arsenal in 2013

Quite what they will achieve remains to be seen. Ozil believes it will be the Premier League title. Yet, will he win it before he leaves the club?

'I have one more year on my contract. I hope so. I want to win the Champions League and the title. I see this club as having the potential to win these trophies.

'You can't think we won't win it in the future because we haven't done so in the past. We haven't been consistent in the past. We've had great first halves of the season and then not had the same in the second half of the season, or the other way round.

'As a team, we need to be more consistent over a season, show more ambition, more strength, more will.'

Then there is Arsenal's Champions League experience. For seven consecutive years, the club have been eliminated in the last 16 of the tournament but never more humiliatingly than the 10-2 aggregate defeat against Bayern Munich this season.

Ozil celebrates his strike against West Ham with Mohamed Elneny and team-mates

The 5-1 loss in the first leg at the Allianz Arena was a chastening return to Germany for Ozil and he acknowledges his role in the failure.

'Of course my performance wasn't top, neither was the team's,' he says. 'In the first game, our first half was good. But then in the second half we collapsed.

'For offensive players it's hard when you don't have much possession and can't make your contributions.

'After the first game, I didn't have as much faith that we could turn it around. The defeat was bitter for me and the whole team.

'When every year you see the chance, think it's really possible against big teams and then have a big defeat, it affects me because I've always wanted to achieve big goals and always will. I wanted to win the Champions League.'

Yet amid his self-reflection, there is also a clear sense that the club themselves will need to do more.

'I think the club know they need to strengthen. But what's most important is the manager's opinion. He and the club will make the decision.

'When you look at our squad, it's not as broad as Bayern's or Real Madrid's. In the Champions League, that's not enough, especially against big teams, because they have more breadth in their squad.'

Ozil looks on during Arsenal's Champions League last 16 defeat by Bayern Munich

Talks on the new deal the club have offered Ozil will resume this summer. He gives no definitive prediction on how those negotiations will go.

'It makes me happy, that the fans support me, that my team-mates and the club support me.

'But football is my priority, we have aims with the team to reach the Champions League. In the summer there's enough time to talk about other things.

'I'm very happy. I have a connection with the club. I love London, it's great to live here but I can't say today what will happen in the future. In the summer we'll definitely talk.'

Were Arsenal to remain fifth and he stayed, it would be the first time he had missed out on the Champions League since 2010.

'I haven't thought about that. The club comes first, not Mesut Ozil or anyone,' he says.

'The team have the aim to reach the Champions League and I'll fight for that. In the summer we have enough time to talk about the future and we'll do that.

Of course, Wenger's own future is also in some doubt.

Ozil, who first spoke to Wenger in 2010, before he joined Real Madrid, has cited the Arsenal manager as the principal reason why he joined Arsenal. Wenger staying, it seems, is a crucial factor.

'It's not just important for me but for the whole club,' he says. 'It's important to know if he stays or if he goes. We need to think towards next season.

'He's very important. In my career I've always made decisions not just because of clubs but managers, too. As a footballer, it's important to have the manager's trust and believe they can develop you.

The German international believes that Arsenal have the potential to achieve a lot

'When I went from Madrid to Arsenal, I came for him because I told him at the time he'd be my first option. That was the case. We still have a super understanding today.

'I have his trust, he's a superb coach. He's been successful for many years, he's been here for 20 years and has always manages to get Arsenal to reach the Champions League, making Arsenal a big club. He deserves to be shown respect.'

Indeed so. And yet this Arsenal team will only have the respect commanded by Wenger's previous sides if they can match them in the Premier League or surpass them in the Champions League. Ozil knows as much.

'As a player you're never satisfied. As a player you want more — you want to win the League. I'd like to win the Champions League too, because it's the biggest thing in club football.

'This club is big, they have potential to achieve a lot and I hope that works better in the future.'

Therein lies the conundrum. The club is indeed big and Ozil is an exquisite player. Yet somehow that hasn't been enough. His challenge now, aged 28, is to lead this team into uncharted territory.