The family of the popular Spaniard, who won five majors and was instrumental in growing golf’s popularity, announced he had passed away at 1.10am today due to respiratory failure.
Ballesteros, 54, who announced his retirement from golf in 2007, collapsed at Madrid Airport in October 2008 and two days later came confirmation that he had a brain tumour.
He underwent an initial 12-hour operation, but further surgery was necessary before he was well enough to return home and begin chemotherapy and radiotherapy treatment.
“I am very motivated and working hard, although I am aware that my recovery will be slow and therefore I need to be patient and have a lot of determination,” he said at the time.
“For these reasons I am following strictly all the instructions that the doctors are giving me. Besides, the physiotherapists are doing a great job on me and I feel better every day.”
After a second course of chemotherapy at Madrid’s La Paz Hospital in February 2009 he said on his website: “The results of the check-up were really positive, better even than the first ones.”
Two more courses followed and four months later Ballesteros made his first public appearance, saying it was “a miracle” to be alive.
In December 2009 he appeared on television to receive the BBC’s Lifetime Achievement Award at the Sports Personality of the Year event from his former Ryder Cup partner - and now captain - Jose Maria Olazabal.
He won the Open three times, the Masters twice and played an inspirational role in the Ryder Cup, helping Europe to lift the trophy in 1985, 1987, 1989 and 1995 before captaining them to another victory at Valderrama two years later.
Ballesteros turned professional in 1974 at the age of 16 and made his first huge impact two years later by finishing second in the Open alongside Jack Nicklaus at Royal Birkdale.
His first major title came in the 1979 Open at Royal Lytham, he then became Masters champion in 1980 and 1983 and lifted the Claret Jug again at St Andrews in 1984 - his greatest moment really - and back at Lytham in 1988.
After a total of 87 tournament wins, his retirement came following years of battling an arthritic back and knee problems.
He was planning a farewell appearance for British fans at last year’s Open at St Andrews - not in the main event, but in the four-hole Champions Challenge - but was not well enough to travel.
Only last month Phil Mickelson decided on a Spanish menu for the Champions Dinner at The Masters at Augusta in honour of Ballesteros.
European Tour chief executive George O’Grady said: “This is such a very sad day for all who love golf.
“Seve’s unique legacy must be the inspiration he has given to so many to watch, support, and play golf, and finally to fight a cruel illness with equal flair, passion, and fierce determination.
“We have all been so blessed to live in his era. He was the inspiration behind The European Tour.”
The flags at Real Club de Golf El Prat will be flown at half-mast in him memory for today’s third round of the Spanish Open, while the players will wear black ribbons and there will also be a minute’s silence.
Bernard Gallacher, who captained Ballesteros in three Ryder Cups between 1991 and 1995, said: “He felt it was his duty as the best player in the world to inspire the European team.
“When I became captain in 1991 he was still one of the best players in the world and he former a formidable partnership with Olazabal, virtually unbeatable.”
Ballesteros also delivered an inspirational message to Colin Montgomerie’s victorious team at Celtic Manor last year, and Gallacher added: “Seve’s best golf was played in the 1980s but he was still inspiring this new generation of golfers - the Martin Kaymers, the Ross Fishers, we’ve heard from Lee Westwood how as a young boy he would watch Seve and everyone would want to copy and emulate Seve.
“Every European Tour player today should thank Seve for what they’re playing for. America had Jack Nicklaus and Arnold Palmer - Seve was our Arnold Palmer and Jack Nicklaus rolled into one.
“You can’t speak too highly of him, Seve was Europe’s best ever player.”
Ballesteros’ former caddie Billy Foster remembers him as “an absolute gentleman, the ultimate warrior.”
Foster added: “There’s not many players I’ve worked for in my time that have that aura about them. It was a special time - I was probably 25 years old, I’d caddied for maybe 10 years, and I got the ultimate dream chance of working for an absolute superstar.”
Julian Small, chief executive of Wentworth Golf Club, where Ballesteros won five times, said: “Seve was a great champion. He was a swashbuckling man, a handsome man who really entertained the crowd.”
The Seve Ballesteros Foundation, which Ballesteros set up following his diagnosis to help others with brain cancer, was the chosen charity for the BMW PGA Championship at Wentworth.
Mr Small said: “He played such a fantastic game of golf. Wherever Seve went there was always a huge crowd. He saw the West course here at Wentworth as one of his favourite places to play.
“He is the pioneer, he is the person that has changed the shape in many ways - especially with the general public - of European golf. His way of playing, his whole charisma, he brought it to new markets, to new people, to new populations. He is Europe’s version of Arnold Palmer, he is the person that really made that big difference.
“Seve and the Ryder Cup - it’s legendary what he did. To think that Colin Montgomery had him on a speakerphone to the team last year down at Celtic Manor is a sign of how the professional golfers were inspired by him.
“Seve was in many ways the king of the recovery shot. I always remember a wonderful shot - I think it may have been in 1991 - over a shot that was a very tricky shot and a very important shot in the game. A little boy behind him was rattling his coins in his pocket and Seve stepped back and said to the little boy, ‘Are you nervous?’ He said, ‘Yes’ - he said, ‘So am I!’.”
Ballesteros had joined forces with Cancer Research UK to raise money for the charity to help fund research into brain cancer.
Today the chief executive of Cancer Research UK Harpal Kumar said: “We’re very saddened to hear that Seve Ballesteros has lost his fight against brain cancer. I had the great honour of meeting Seve and his family at his home in Pedrena when we first established the Seve Ballesteros Foundation partnership in 2009 and my thoughts are with his family at this very difficult time.
“Seve was a hero to many for all he achieved during his career, but never more so than in the months after he was diagnosed with a brain tumour. His personal battle against the disease, and his determination to help others through his Foundation, was truly inspirational.
“Seve’s experience brought a much needed spotlight onto brain cancer and Cancer Research UK was honoured to join forces with his Foundation to work towards our shared goal of beating brain cancer. It’s a huge challenge but one that Seve was committed to making a reality.
“The partnership with Cancer Research UK has already raised over £700,000 towards ambitious and vital research that will help improve diagnosis and treatment of brain cancers in the future.
“Today we have lost a man who will be much missed and remembered the world over for what he achieved both on and off the golf course.”