From the time he was 16 and the Australian boys champion, Jason Day looked like a major winner in the making. But the road was uncharacteristically long for Day, the Queenslander with the amazing, all-round game.

Near misses at the Open Championship in the same year, and previously at Augusta National in 2011 and 2013, only added to his sense of frustration.

But in 2015, it came together in a hurry. Day won the PGA Championship at Whistling Straits in Wisconsin, in the process seeing off Jordan Spieth’s challenge and becoming the first man to post 20-under par in a major.

It was August 20. By September 20, Day had won a United States PGA Tour playoff event, the BMW Championship at Conway Farms near Chicago to reach the No. 1 world ranking. In the space of weeks, Day had ticked off two of his life goals.

At the PGA, he was dominant from the start, and two ahead of Spieth entering the final round before shooting a 67 to win by three. Spieth, remember, had already won two majors for the year and was ominously poised, but Day birdied four of the first seven holes at Whistling Straits and never looked threatened.

At the 11th, he monstered a 350-metre drive into a narrow fairway and Spieth, 70 metres behind him, yelled out: “You’ve got to be kidding me!’’ Day flexed his biceps and made another birdie on his triumphal march.

“It’s just a matter of how much do you want it?” he said. “And I really want it. I mean, I’m willing to put my body on the line just to get a taste of that greatness.”

At Conway Farms in September he was even more dominant, winning for the fourth time in six starts, by six shots. As a boy working with his caddie-coach Col Swatton, he’d forged an idea in his mind that he could be the No. 1 player in the world.

Now, he had the mantle – just the third Australian man behind Greg Norman and Adam Scott to do so. “Knowing that right now there's no one on this planet that's better than me, that's pretty cool," he said. "That out of all the golfers that are in the world playing right now, that I'm the best. It's such a good feeling.’’

The feelgood aspect is compelling. Day had a tough upbringing in Beaudesert, north of Brisbane, with an abusive father who died when Jason was 12. Day himself lurched into heavy drinking as a teenager and it was not until Swatton's intervention that he settled into his passion for golf. Significantly, he and Swatton embraced when he clinched his first major.

The aftermath is worth noting. In September, 2015, Day looked like he might win 10 majors and be world No. 1 for a long time. His game had no weakness. But persistent injuries began to bite, and the game stands still for no one. Five years on, he has not added to his tally of one major.

But even if he never swung a club again, Jason Day is a great of Australian golf.

The 2015 PGA highlights