They did not believe Ashok Rathod when he told them. Juan Mata, Manchester United star and World Cup winner, was coming to Mumbai. And not just Mumbai. To the 60,000 strong slum of Ambedkar Nagar to spend time with the children of the OSCAR Foundation. "I told people but they said, 'Ashok, you are lying!'" he tells Sky Sports.

"The children got to play football with Juan. It was hard for them, and for us as well, to believe that this big football superstar was in the slums of Mumbai. He met the children and he went everywhere. He was not thinking about who he was, he was interacting with everyone. It was such a shock for them. How could he be in Mumbai?"

Ashok Rathod showing Mata the work of the OSCAR Foundation [Max Cooke]

And yet, Mata did indeed visit the slums this summer. Fourteen of the youngsters have just made the return trip to Manchester, receiving a guided tour of Old Trafford from the player earlier this month. On that same day, Mata launched a photo exhibition of his visit to India at the National Football Museum in the city to help raise further funds for the cause.

That cause is a noble one. Rathod helped launch the OSCAR Foundation while still a teenager in 2006. Through sport it helps underprivileged children become role models and appreciate the value of education. Mata was overwhelmed by the warmth of the response from the children but also by the vision of the man guiding them on their journey.

"Ashok is a great character and I am really happy that we met," Mata tells Sky Sports. "Straight away, we got on very well. He has created something really special that is helping disadvantaged children in Mumbai. He is very young but he has that passion and drive that make him a born leader." Many would now say the same of Mata himself.

Rathod and Mata were both born in April 1988 before setting off on very different paths. But now they are united in a Common Goal thanks to the Spaniard's historic pledge to contribute one per cent of his salary to various initiatives around the world. The campaign is gathering momentum with four more World Cup winners already signed up.

Mata went to Mumbai in the summer before helping to launch Common Goal

It was not an impulsive decision as Mata's long-time partner Evelina Kamph, who accompanied him on the trip to India, explains. "Ever since I met Juan, he has always wanted to do something," she tells Sky Sports. "I am very proud of him because a lot of people think about doing it but to actually put yourself out there is amazing.

"So many people ask football players to get involved in different projects and charities that I suppose it is difficult finding your way in that jungle. I guess you just have to go with your gut instinct and Common Goal felt right. For us to be able to go to India and see the changes that the funding could make to children's lives was so important."

Mata and girlfriend Evelina Kamph swapped the red carpet for the Mumbai slums

Kamph's role should not be underestimated. Though happier in the background, she is a well-educated woman with a master's degree in osteopathy and her supporting role in India extended to taking many of the photos that make up the exhibition in Manchester. Mata himself clearly sees this as a joint venture.

"Evelina has been a really important part of all of this," he explains. "Not just by taking a lot of the photos but in sharing her opinions on many different things and bringing joy to our trip to India. We have so many great memories together as a result. We both inspired each other." They were both inspired too.

"It was such a different experience for me," says Kamph. "I'm from Sweden and studied in England so I've not seen anything like that before. You expect people in those circumstances to be a certain way. But they are so warm and the kids are so curious. They want to know everything. It sounds a cliché to say it changed my perspective on things but it really did.

"The response Juan got from people on the street and from everyone also reminds you that footballers are in such a privileged position in terms of how happy they can make children just by being themselves. I envy that. They can make a kid's week, month or year just by greeting them or playing football with them. It's an amazing thing. I am privileged to see it."

In the Old Trafford dressing room (Picture courtesy of Juan Mata/Instagram)

For the 14 children, the thrill of the experience was obvious in their songs and their smiles. "Everything is new to them," says Rathod. "They are the first people in their families to have a passport. They are the first children to travel in a plane. It is hard for them to believe. They keep asking Juan question and they keep thanking me. They think they are in heaven.

"We want the 14 kids who are on this trip to become ambassadors for us. They will go back and tell people about their experience and it will give hope to other children. They can also dream big and they can achieve. They understand from this trip the importance of education. They will go back and be role models and an inspiration for many others.

"These children are very disciplined and they are very positive. They know they have been selected out of 3,000 children so they know that they are lucky. We want to give them all a better life and a better future. Through this exhibition, more people will be aware of the OSCAR Foundation and hopefully they will feel that we are making a difference."

Mata is already doing that and while there was a promise to return to Mumbai as he hugged the children during their goodbyes, there is also the knowledge that this is just the start of his new life. He has plans to visit other countries and embark on new projects too. Colombia has been mentioned as a possibility, North America as well.

For both Mata and Kamph, the commitment already feels like a lifelong one - a prospect they appear more than happy with. "This is something we will remember a lot longer than a holiday," she says. "If I can exchange my holidays for things like this, that would be the best thing." Mata agrees. "I would like to do these things as often as I can," he adds.