It was shortly after Aaron Mokoena had met the Queen at Buckingham Palace last month that Jacob Zuma, South Africa's president, felt the need to reinforce the introduction. "The president pulled me to the Queen," Mokoena recalls, with a smile, "and he said to her: 'You've got to know this man because he is the one who will make sure that South Africa wins the World Cup. He is the captain of the country.' It was really fun."

The moment, during Zuma's state visit to the UK last month, was one of those when you wished you were there. Wayne Rooney, Fabio Capello, Elizabeth II - your boys are going to take one hell of a beating. What did Her Majesty make of it all? "Well, the thing is she is well informed," Mokoena says. "She obviously knew that the finals were in South Africa and she also knew who I was. But not to such an extent so the president had to make a point."

Zuma was not joking. "When Zuma was here for his visit, I had the opportunity to sit down with him a couple of times and have a discussion," Mokoena says. "He just got straight to the point and he said to me that you have to make sure we win. He loves football so much. I didn't know but he's a Liverpool fan and he used to play football himself. He used to be a captain of a team in the prison with Nelson Mandela on Robben Island. But that's exactly what he said to me: 'You've got to make sure that the country wins.'"

South Africa have qualified for only two previous World Cups and they have won no more than a solitary group tie. If history is against them, then so too is recent form. They failed to reach January's Africa Cup of Nations, for the first time since 1994, and, of their 10 matches this season, they have won only two – against Madagascar (ranked 154th in the world) and Zimbabwe (113rd). South Africa, who have been drawn with France, Mexico and Uruguay in the group stage, are ranked 88th. Only North Korea (105th) take a lower ranking to the finals.

But Mokoena refuses to consider anything impossible and why should he, after the manner in which his Portsmouth team have diced with winding-up threats this season only to reach the FA Cup final? It was Mokoena's 120th-minute winner in the third-round replay at Coventry that got the fairytale started and his outstanding performance in the semi-final upset of Tottenham that helped to carry them into next month's showpiece with Chelsea.

"It's been a fantastic run for us and especially lately, because we know that it's the only thing we had after our points deduction and relegation from the Premier League," he says. "We need the FA Cup more than anything and there's absolutely a parallel between Portsmouth and South Africa. It's exactly the same. We need the FA Cup more than anything and South Africa need this World Cup more than anything. Hopefully, we can do as well in the World Cup as we have done at Portsmouth in the FA Cup."

The longer you listen to Mokoena, the more convincing his arguments sound. It is not a surprise to discover that he wanted to be a lawyer when he was younger, only for football to come calling, or that he intends to apply to law school once he has hung up his boots.

Mokoena, South Africa's most capped player, says that his squad boasts a wealth of talented youngsters, who are hungry to make their names and possibly secure transfers to Europe. They have recently returned from a four-week training camp in Brazil, in which they enjoyed encouraging friendly results against opposition that included Santos. Then, there is the coach, Carlos Parreira, the Brazilian who led his nation to glory at the 1994 finals. His experience is vast. He has also taken Kuwait, the United Arab Emirates and Saudi Arabia to World Cups.

Above all, however, is Bafana Bafana's 12th man. With their blaring vuvuzelas and mounting excitement, the home South African crowd is champing at the bit to play its part. "We saw what happened at the 2002 finals with South Korea," says Mokoena, of the co-hosts who reached the semi-finals, "and it can definitely be the same story with us.

"We experienced it last summer when we had the Confederations Cup in South Africa and I am sure that the atmosphere will be even hotter at the World Cup. People are so over the moon to have the World Cup and we are going to show how much it means to us. The Confederations Cup, when we reached the semi-finals, was a good rehearsal and it's absolutely possible that we can do well at the World Cup.

"I think it's good to be underdogs. I said before the Confederations Cup not to write South Africa off and we surprised people then. I'm going to say exactly the same thing again. Don't write off Bafana Bafana before we've even kicked a ball."

The responsibility on Mokoena's shoulders at the African continent's first World Cup will be huge but, in a sense, events at club level have prepared him well. The 29-year-old only joined Portsmouth from Blackburn Rovers last summer but, such has been the emotional intensity of the week-to-week ride, it feels to him as though he has been there a lifetime.

"I must say it's been tough," Mokoena says, reflecting on Portsmouth's ownership changes and slump into administration. "But in the semi-final against Tottenham, we showed what character we have. I'm sure a lot of people elsewhere wouldn't have coped with the situation that we've had. The important thing is that there is nothing impossible in life. Do you want to take the easy way out or do you really want to fight it through?"

Mokoena has always had a steely side, from his formative days in the township of Boipatong near Vanderbijlpark, the site of a massacre in June 1992 when Inkatha party members, aided by the police, swept in by night to kill more than 40 people, including pregnant women and children.

"I remember I was on my way to school and people were coming back crying and that's when we heard," he says. "People were murdered at night. It was awful. After the massacre, there were a lot of rumours saying that these people wanted to kill the young boys. So my mum had to protect me in any way and she decided to dress me as a girl. She also took me to this community hall where there was enough protection for people from the township, especially the boys.

"It wasn't an easy upbringing. It was a township and in townships anything is possible. My brothers and sisters really experienced apartheid while crime-wise it was absolutely bad but I always had the support and protection of my family."

Mokoena also had his studies. "I was an academic boy," he says. "I was into mathematics and I loved science. I wanted to study further but, because of football, I couldn't do what I wanted to do."

His passion for education has seen him lend his support to the 1GOAL initiative, which aims to get all children into school. "The thing that encouraged me was that there are so many kids who don't get the chance to go to school," he says. "We are talking about 72 million kids worldwide who don't get the chance.

"I chatted at length to President Zuma about 1GOAL. He is absolutely into education and in South Africa a quarter of the budget goes to education. That shows the president is trying to give younger people the chance to have a better life. Apartheid jeopardised the opportunity for kids in South Africa to be educated and he is trying to change that. It is one thing he wants to leave as his legacy."

Zuma has a different demand of Mokoena. The FA Cup final is merely the warm-up.

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