Victory by Lin Yuxin and the performance of China was the storyline from the ninth staging of the Asia-Pacific Amateur Championship at Royal Wellington Golf Club. Four Chinese amateurs finished in the top-five placegetters, topped by the 17-year-old left-hander from Beijing.

On the Thursday, Fox Sports’ Paul Gow had singled out Lin as the player to beat in Wellington. Having observed his powerful ballstriking and penetrating trajectory on the range, Gow felt the schoolboy ranked No.338 on the World Amateur Golf Ranking had the game to win the most coveted tournament in the Asia-Pacific.

And so it proved. Lin accumulated 22 birdies and two eagles over 72 holes. He finished three clear of runner-up Andy Zhang despite seven bogeys, a double and a triple. He was the third player in Asia-Pacific Amateur history to shoot four rounds in the 60s, joining Hideki Matsuyama (the winner in 2010) and Cameron Smith (fourth in 2011). Both have since firmly established themselves as professionals, ranking fourth and 89th on the Official World Golf Ranking, respectively.

However, one significant victory is no guarantee of long-term success. On the Saturday I wandered over to the practice putting green. Two players who missed the cut were there working on their games. I had met one of them six years earlier at the Aaron Baddeley International Junior Championship in Qingyuan (a relatively small Chinese city with a population of 3.7 million). After seeing him win that tournament with a cross-handed putting grip, I wrote: “I think I’ve seen the future of golf. He is 13 years of age. He is Asian – and Chinese. His name is Guan Tianlang.”

The following year Guan was a surprise winner of the Asia-Pacific Amateur at Amata Spring near Bangkok. He surprised even more pundits when he made the cut at the 2013 Masters, becoming the youngest player ever – at 14 – to make the cut in a US PGA Tour event. He did so even with a one-shot penalty for slow play in the second round. Such was his proficiency with an anchored belly putter, Guan didn’t have a three-putt for the entire week at Augusta where he tied for first in putts per round with 27.

Guan turned 19 on the eve of the Asia-Pacific Amateur at Royal Wellington. On the Friday I came across him at the first green where he had left his approach just short of the putting surface. He hit a poor chip and then missed an eight-footer for par. Guan’s body language – frustrated and dejected – was a world away from the composed, purposeful young lad in Qingyuan.

Intrigued as to what had transpired since, I loitered around the practice putting green on the Saturday, standing 25 metres away from Guan on the other side of a white picket fence. He had planted a set of tees through which he was attempting to hole six footers (not dissimilar to the putt he had missed on Friday).

Standing directly on the through-line, I waited to watch him hit a putt. I waited. And I waited. After a minute or so, Guan stopped and walked over to his bag and sipped on a bottle of water. After another minute he walked back onto the green and crouched down. He picked up a ball, lined it up and … then put it down and picked up his phone and started playing with it.

I was watching Guan. He knew I was watching him. And I knew that he knew I was watching him. This all took three or four minutes, upon which I walked away to leave the young man in peace.

How did it come to this? So perturbed by others watching his every move. It was tempting to draw a parallel with Ian Thorpe, a teenage superstar who became troubled, indeed tortured, by the burden of expectation.

Guan has slipped to 1,993th on the WAGR. He is no longer able to use an anchored belly putter. And he hasn’t benefitted from a growth spurt that would enable him to overpower golf courses like so many amateur rivals.

Ritchie Smith, the Perth-based coach of Minjee and Min Woo Lee (the only brother and sister to win the US Junior titles), suggested Guan is burnt out. The first thing Smith would have him do is hit some flop shots with a lob wedge, reasoning it would loosen him up.

After all, the home-schooled only child has been playing since age 4 when his dad, a former doctor and fanatical golfer, took him to a driving range. Guan learnt about the game by watching professional golf on TV. He’s now a freshman at the University of Arizona and finished 77th in his first collegiate start.

I hope he rediscovers the confidence that propelled him to such early success. But for the time being, Guan Tianlang is a cautionary tale that not all that shines brightly will shine forever.