There are stats that tell us who hits the ball furthest, closest to the pin and holes the most putts, but there’s another vital part of golfing success that’s far more difficult to measure. There’s no ranking for mental strength – but if there was, it’s safe to say Jordan Spieth would be right at the top of it.

At just 22 years old, the two-time major winner has developed one of the strongest minds in the game. While he may not overpower golf courses like Rory McIlroy and Dustin Johnson, his incredible mind has helped him dominate golf in 2015.

“Spieth is an exception to just about every rule in that he combines a one in a million natural talent with an incredibly mature head and grounded personality,” says top mental performance coach and author of ‘Silent Mind Golf’, Robin Sieger. “A lot of this is down to his parents, who deserve a lot of credit for bringing him up the right way, and his sister, Ellie, who was born with a neurological disorder. Her condition and friendship has boosted his maturity and helped to keep him grounded.”

There is no doubt Ellie is an important ingredient in her brother’s mental jigsaw – in the aftermath of his triumph in this year’s Masters, Spieth described his 15-year-old sibling as someone he “loves to spend time with” – but she is by no means the only piece.

There are seven experiences in his fledgling career that have contributed to the evolution of a major-winning psyche.

Spieth won three tournaments and was the key player as the University of Texas golf team claimed the NCAA Championship title during his first year at college. He won 2½ points from three matches at the 2011 Walker Cup and was top of the Amateur World Rankings midway through his second year at college when he decided to turn pro – aged just 19. It was a move some observers called risky because he had no status on the Web.Com or PGA Tours. “There were some voices, especially because I didn’t have status anywhere, but I just kind of threw them out,” says Spieth. “I didn’t listen to them and I never looked back. I knew that through sponsors’ exemptions I would have enough opportunities to start strong and take care of things by myself.”

Sieger says: “He was ready for a bigger stage and he knew it. He had a history of winning and believed he was prepared to win at the highest level. He understood being a top amateur doesn’t really have a bearing on your professional career and he recognised that the PGA Tour was the only real option for him. He’s also very goal oriented and he had the self-belief, commitment and determination to set lofty goals and pursue them at a young age.”