Johan Djourou was adopted by his father's wife. Think about that for a moment. Arsenal's Ivory Coast-born Switzerland centre-half has enjoyed a breakthrough season, amid all the angst on a collective level at the club, but the story of his formative years is the most remarkable. It has shaped his world view and imbued him with a boundless positivity that, at times such as these, can also make him a persuasive spokesman for the Arsenal defence.

"It's a difficult story," Djourou says. "My dad is Ivorian and he was married to a Swiss lady, called Danielle, and they lived together in Geneva. But he went to Ivory Coast and he had this thing with my biological mother, Angeline, so that's where I came from.

"Danielle could not have kids and my father said to her: 'Look, I had this thing … my son was born, I made a mistake,' and she just said to him: 'Let's bring him here and we can adopt him.' My dad was in contact with my natural mother. So at the age of 18 months, I moved from Abidjan to Geneva.

"I have two mothers, which for me is great. It has given me so much and I have to say that without my adoptive mum I would maybe not be here. When you are in Africa there are a lot more difficulties and I was lucky enough to escape that. Other players like [Emmanuel] Eboué and Kolo Touré have made it through there but when you are European you have more options.

"Danielle is an amazing woman. There is a lot of jealousy in the world today and many people wouldn't accept those situations but she just took it in her stride and made the best of it. She had been betrayed but she did something so great to bring me in."

If the tale feels fit for the pages of a novel, then Arsenal's season and, indeed, their recent history, has provided many more outlandish plot lines. Djourou is certainly at the right club.

Until the end of February Arsenal were competing on four fronts and threatening to end their six-year trophy drought. But a dismal run of results, beginning with the Carling Cup final defeat by Birmingham City, has brought them to their knees and one final blow now beckons. Manchester United would take a significant step towards being crowned champions in Arsenal's backyard if they were to win at the Emirates on Sunday.

Djourou has watched the winds of criticism buffet the club. The most common accusation is that the team have lacked the toughness to take the final and most difficult steps. Arsène Wenger has heard his project questioned, not least by the captain, Cesc Fábregas, who said that the club faced a fundamental decision, concerning whether they "go out to win or to develop players", but everyone in the game seems to have had a say.

Djourou has a different take. He arrived at Arsenal from Etoile Carouge in Geneva on 1 August 2003, three days before Gaël Clichy and six weeks before Fábregas, making him the club's longest-serving current player. It was a time of excitement, when promise was about to gel into Invincible achievement, and Djourou argues that Wenger's present crop are on a similar threshold. They have suffered this season, chiefly because of how close they have been, but the glory, he says, is "around the corner". His conviction is so total that he is comfortable drawing the boldest of allusions.

"The Invincibles team of 2003-04 had great players but what people forget is that before that similar questions were asked about them," Djourou says. "So for us it's just a matter of 'let's win' and then the opinion will change. I don't think it's a massive difference because we have the same qualities and maybe better qualities than the unbeaten team. I'm not going to compare the two. I am just saying that we are not far short."

The problem, of course, has been that victories when they have mattered the most, the results that have immortalised the teams of the past, have proved elusive. It is the easiest thing to say that one or two big wins would alter perceptions; quite another to get them. The Carling Cup final defeat was perhaps the most painful and Djourou pulls no punches in his assessment.

"On the day it looked like Birmingham wanted it more than us," he says. "Why? I don't know. That's a good question. Maybe, the occasion for them was different. The defeat was a big blow because when you are in a final all you have in your head is to win. You put yourself in a winning position but, when you realise you've lost, it is a massive kick. You think it's the end of the world. The result had a massive impact on us."

Djourou is a true Wenger disciple. Close your eyes and listen to his reasoning, his logic, his yearning and it could be the manager himself. "I don't see Man U as being better than us this year," Djourou says. "They have just been more consistent. Quality-wise, I don't see a better team than us." He argues that Arsenal have merely been on the wrong side of the finest of margins, yet he knows that it will turn for them, as it has for him.

The 24-year-old missed virtually the whole of last season due to knee surgery but he has been the pick of Wenger's defenders this time out, showing not only his class but his character to come back. Until last Sunday's defeat at Bolton Wanderers Arsenal had not lost a league fixture when he played, a run of 18 matches.

Djourou's journey from African poverty to western European opportunity has given him many things, not least a sharp social conscience. His Kémi Malaïka Foundation has set up a school in Senegal to provide "the best education possible" for 120 children. Although Djourou declared for Switzerland, a decision based on his respect for the country that raised him, he will never forget his African roots. Then, there is also his patience and sense of perspective. "You can say that Arsenal have lacked a championship mentality because we haven't got winners, who have won many cups, but that's a thing you build," Djourou says. "And in this group we definitely have the ability to become that. It's not far away, that's the whole thing.

"When the club signed Thierry Henry, he hadn't even been playing at Juventus, the same with Patrick Vieira at Milan while Freddie Ljungberg came from a little Swedish club. But look at what they became. People have to remember that it's a foundation of work and not everything works as soon as they want.

"The Invincibles team was a project that was not made in one year. It was piece by piece by piece. We have to keep the faith in this project and we just want to win to show the world that the boss is right. It takes a lot of courage to keep going with your own way."

Arsenal's players have grown used to the incessant questioning but Djourou might reason that his family tree has prepared him well. Each detail of it demands fresh inquiries. Djourou's father, Joaquim, fathered a second son with Angeline, who already had a daughter from another relationship. Why was he not taken to Geneva, along with Djourou? "It was a bit too much," Djourou says, "for my father to say, 'I've got another one, let's adopt him as well.' So it was just the first one."

Joaquim would separate from Danielle, remarry and father two more girls and one boy. He stayed in touch with his ex-partners and endeavoured to provide for all of his children, which helped Djourou to remain close to his brother and four half-siblings in two continents. He says that he "loves" his father, who clearly "loves the women", but how has Djourou's relationship with Angeline developed? And how has Danielle contended with that?

"When I was 15, just before I signed for Arsenal, I went back to Abidjan for the first time since I was a baby to see my mother," Djourou says. "It was just crazy because I was with my adoptive mother. When we arrived at the airport, my biological mother was in front of me but I didn't know. I had to ask my adoptive mother: 'Who is my mother?'

"She knew that she walked with a limp, and she said: 'That's her.' But the meeting was difficult because I didn't know what to say to her. Danielle had to say: 'Angeline, you need to talk to him.' So that's where it started."

Arsenal's search for the happy ending goes on. Djourou will not stop believing.