This is quite hard for me to believe," Cesc Fábregas says as he takes off his baseball cap and gently bends back its rim in a gesture of genuine surprise. "I came to London in September 2003 and so next week it will be four years since I left Barcelona forArsenal. Everything has come so quickly that it's unbelievable. I was 16 then and now I am 20. A lot has changed."

The young Spanish midfielder, who symbolises the new heart of a football club caught in a state of unsettling flux, was once just another foreign apprentice trying to find his way in a strange country. But Fábregas has become the player they revere most at Arsenal, a figure second only to Arsène Wenger in terms of his symbolic significance to Arsenal's future. An unresolved battle over ownership of the club has been framed by the departure of David Dein, Wenger's great friend in the boardroom, and further losses on the field itself.

Thierry Henry's move to Barcelona at the start of the summer underlined Arsenal's dependence on Fábregas. If he had accepted a persistent offer from Real Madrid to line up against Henry in La Liga, Arsenal would have been in disarray. However, confirmed as their talisman, Fábregas believes the transfer of the French striker could usher in a defiantly positive transformation. He is intriguingly candid in admitting that Henry's mere presence often intimidated his team-mates.

"Thierry is the best I've ever played with. There's no doubt. But there was this other factor. He is Thierry Henry. When I came I felt I was low and he was high. It was a big difference and for a long time I was intimidated. When I had the ball I felt I had no choice but to look for him. I did this because, one, he is the best and, two, because I had the feeling I had to pass it to him. He has such a strong character that he almost made you feel this way. I needed him to say, 'Look, you don't always have to play the ball to me.' Once he said that, I was free and I gave him even more assists. Thierry is a very intelligent man and I wish him all the luck in the world at Barça."

Yet when Real pursued him, with the president Ramón Calderón calling Fábregas personally, was he not tempted to follow Henry back to Spain? "No. I always knew I would stay. Especially when Thierry went, I knew it would be a very important year for me at the club. It is a personal challenge but also a challenge for the team as well - to win something without Thierry. He was such a winner and of course we will miss that, but we have other options now. And if we can make it then it will mean we are a great team. We are starting a new project without players like Thierry and Patrick [Vieira] but we are capable of something special."

Wenger's impact on his most glittering protégés - Vieira, Henry and Fábregas - is indisputable. It explains why Arsenal's entire future often seems to rest on their manager remaining at the club. "I believe Arsène will sign a new contract. Definitely. I think he will stay because he knows Arsenal will not be the same without him. This is perfect for me because I am learning from Arsène all the time. He speaks to me even more now. In the first years I was here he never put any pressure on me. But he has so much knowledge that all you have to do is listen."

Fábregas is understandably cautious when asked about Dein's acrimonious exit. "Well, that's when everybody started to think whether or not the boss would go or stay. I don't know whether that had anything to do with Thierry's decision but we must just think about football and winning matches and titles. Who knows exactly what will happen in the future? But right now we are all together and we want to win. I definitely feel we can win something this season.

"I have been training with these guys a lot and this team has quality and desire. They get angry whenever we lose. We get upset with each other when we don't do things properly and you need this passion, this desire, to win things. This team has it. But it's no good me just saying it to you in the newspaper - we have to turn the words into reality."

And so, committed to both Wenger and the club, Fábregas plans to galvanise a youthful side renowned for producing sublime if often wasteful patterns of play into formidable challengers in both the Premier League and Europe. The last four years have instilled a toughness and an equilibrium which suggests he might prove equal to the task.

"I am proud of how I coped, but I knew what I wanted even before I came here. I knew if I had to be alone for two years then I could do it - as long as it meant first-team football. If I could show everybody what I could do on the pitch then there would be no problem at all with the loneliness. But I want to think about Manchester City and Sparta Prague now."

Another big week looms for Fábregas and Arsenal. Following today's home game against City, the Premier League's unexpected leaders after three straight victories, the second leg of a Champions League qualifier against Sparta Prague awaits on Wednesday. In Prague, led by a combative Fábregas, Arsenal withstood an abrasive challenge to win 2-0. That should be a telling score, guaranteeing the Champions League millions which will go a little further in reducing the massive debt incurred by their new stadium. But defeat today would leave Arsenal eight points adrift of the league leaders with only one game in hand.

Fábregas reveals, with a wry laugh, how such urgency fuels an obsession with football that makes him sound positively Wenger-esque. "When I speak to my girlfriend [Carla] at home sometimes she shouts at me because, at the same time, I am watching a small game from Holland, between two ordinary Dutch teams. Or maybe I am watching a replay of a game I've already seen four times. She gets cross with me because it's football, football, football! But it has always been like this. Maybe when I am thinking about a game, or watching it again to see what I did wrong or right, then I take time to reflect."

It is a sign of Fábregas's intelligence that, despite his age, he is able to concede, "I am still a bit insecure about myself. Sometimes we finish the game and I feel I play bad - even if we win. Every training session I get angry because I think I didn't do well. But it is completely different when I have to show my character on the pitch. On the outside sometimes I feel worried and blah-blah but on the pitch I'm always confident."

And yet the insecurities still return occasionally, once the heat of a game has faded? "Definitely. I don't need to tell my family when I feel bad because they see straight away how I feel. They are my parents and so, because I'm still young, they are the first ones I turn to whether I'm happy or sad. My girlfriend knows that as well. As soon as they see my face they know how I am on the inside. I talk to them after four hours, when the bad feelings have gone and I am calmer."

His startling youth is confirmed by some of his more relaxed early memories at Arsenal. "When I scored my first goal, against Wolverhampton, I went home and celebrated by drinking a Coca-Cola and eating a Kinder Egg. Even now I go twice a month to visit my old Irish landlady. Noreen is a very nice lady who helped me and Philippe Senderos a lot when we lived with her and her sons. I spent 2½ years there and it was very special. The last 18 months I have been mostly living on my own. My girlfriend was studying in London last year and she was with me but now she has had to go back to Spain to finish her course."

Other familiar faces have also gone. "Apart from Gilberto, Kolo [Touré] and Jens [Lehmann] - only those three - the team has changed a lot since I came. But look at Barcelona. Three seasons ago they were a club undergoing lots of changes because they went six years without winning anything. They changed their team completely and started winning again. Sometimes you need change."

Part of that difference entails Arsenal's readiness to stand up to increasingly physical opposition. "It's true we didn't feel comfortable in the past going to places like Everton and Bolton. But you have to learn and it took two years for us to adapt to this way of thinking. Before, we would know Blackburn and Bolton and the others would play this way and we were not confident we could handle it. Now we are ready to fight. Our objective is to show everybody that it doesn't matter whether teams are physical against us, whether they play the long-ball or good football, we will not lose easily this season."

Even Arsenal's European opposition now attempt to bully them. Sparta's captain, Tomas Repka, a former West Ham hardman, had promised to leave Arsenal's footballers in a clattering heap. "We were having dinner in Prague," Fábregas remembers, "and Tomas Rosicky told us what Repka said. I don't like to hear these words from other teams."

Fábregas duly brought down Repka, forcing him to limp away from a spiky encounter. It looked as if he had taunted the defender when he lay on the ground. Did he relish the "Fábregas the Enforcer" headlines? "No!" he laughs with a bemused shake of his head. "I've been educated to play football, not to kick. Of course, sometimes you have to do it because you want to help your team but I can guarantee I will not change my game."

Yet Fábregas's desire to display the steel to match his visionary talent can only bolster Arsenal's previously fragile brilliance. Approaching the fourth anniversary of his arrival in London another stronger and tougher side to the boy-wonder is already evident - even when he smiles sweetly and protests that "I'm not hard against other people. I'm only hard on myself."

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