Goalkeeper Luca Campanaro, who played for Bedgrove Dynamos FC, was seriously injured in an under-15s away match against Harefield United FC, in west London on Sunday.
His father, Americo Campanaro, posted a tribute to his son on social media, saying: “My son, my life, my angel, fly high my boy xxx.”
Mr Campanaro linked to a crowdfunding page which has so far raised more than £16,000, writing: “My boy is with the angels now, smile and remember him everyone, don’t be sad, celebrate his life, stay as strong as my boy was.”
The organs of the teenager, from Aylesbury, Buckinghamshire, were donated after he died on Monday afternoon “so in this tragic event others may live”, according to the JustGiving site.
Ambulance crews arrived “instantaneously”, according to Ray Green, secretary for Harefield United FC, and Luca was airlifted to the Royal London Hospital.
Mr Green said: “Hats off to the paramedics and ambulance service, they were there that quick, even before the air ambulance.
“Normally when you have a football injury you can be sitting around for an hour, but it was instantaneous.”
Mr Green added: “It was just a freak accident.
“It was just a collision between the two boys.
“From what people were saying, it was the awkwardness of how he fell that was it.”
A statement from Bedgrove Dynamos FC said: “Our thoughts are with Luca’s family and loved ones at this distressing time.
“We also offer our heartfelt condolences to his team-mates and all associated with the club as we now try to come to terms with the tragic loss of our friend and team-mate.
“It goes without saying that everyone at the club is devastated by this news and we ask that the privacy of his family, the players and club members is respected at this incredibly difficult time.”
Dave Garricks, a family friend, set up the crowdfunding page, which has surpassed its £10,000 goal to cover funeral costs.
A statement on the page said any further donations would go to London’s Air Ambulance.
Luca attended The Mandeville School in Aylesbury, where he was sitting his GCSEs in English, maths, science, history, computer science, physical education and a Btec in health and social care.
In a statement released by the school, headteacher Andria Hanham said: “There are no words to describe how we feel in losing Luca from our school community.
“He was an extremely popular boy and well liked by his peers and staff.
“Moreover, he was known in the local community and had innumerable friendships, so this news will shake many, many people.”
In a joint statement by the staff they described Luca as “an energetic, lively, inquisitive, friendly and helpful young man”.
It added: “He always had a smile on his face and he was a popular member of The Mandeville School.
“He will be hugely missed.”
In a statement London’s Air Ambulance said: “London’s Air Ambulance advanced trauma team were dispatched on Sunday to an incident in Hillingdon.
“After treatment on scene the patient was transferred to a major trauma centre by air by the London’s Air Ambulance team.”