The Ormiston Meridian team of Grace Cliff, Jaimie Varga, Che Galleozzie, Emma Astle and Sam Harrison impressed the judges with their ideas on improving attendance at Premier League matches among 18-23-year-olds.
"I am shocked; it feels like a dream," said Galleozzie, 14. "We never expected this to happen.
"The PL Enterprise Challenge has meant everything for months now. We've put a lot of work into this and that's the biggest lesson, that hard work pays off.
"I am going to work hard on everything I do from now on."
Their business proposals focused on introducing a Potters Access loyalty card that offers supporters free travel on special buses as well as access to a fanzone at the bet365 Stadium.
"It was a very honest and realistic business plan," said the judging panel. "They understood the club and its demographic and used market research very well to formulate the ideas."
Although there could be only one winner from the six teams competing at EY's spectacular offices on the banks of the River Thames, judge Alex Scott was impressed by the level of all the teams and had valuable words of advice for them.
"Congratulations to the winners but to everyone else that took part today, I know that feeling of disappointment and how you feel right now but really be proud of what you've done," said the former Arsenal and England footballer.
"I remember going for my first-ever England trial when I was 16 and I got the letter to say that I hadn't made it and that feeling of disappointment.
"Use that. Use the skills that you got today, carry on and be successful and be proud of yourself."
More than 850 young people, 170 schools and 34 football clubs took part in this year's Challenge and the final six also impressed EY chief economist Mark Gregory.
"You are way better than I was at your age," he told the finalists. "You are already coming up with ideas that I never would have thought of.
"There are lots of opportunities out there. Take away the contacts you have made and don't let people tell you you can't do things.
"You have proved today that there are lots of things you can do. Set the bar high and build on this experience."
The Premier League Enterprise Challenge is run in partnership with Comic Relief and gives secondary schoolchildren the opportunity to work alongside clubs to learn about the business of football.
It uses the power of the club badge to inspire young people and develop confidence, teamwork and presentation skills.
Since it started in 2008, it has engaged more than 35,000 young people, bringing them closer to the world of business.