As the bag man for the youngest world No.1 in golf history, Hamilton does everything as well as you would expect a caddy worthy of that position would do it.

Ko uses all of his skills and experience – he reads putts, takes yardage, lines her up, helps with shot selection, and if the results are any guide, he does it all at an elite level.

But there is something else Hamilton does on the course that his 17-year-old boss values above all else.

"You can get mad when you make a silly mistake, but I like how Jason makes some dumb jokes or, I guess, some sarcastic sentences and it kind of makes me wonder 'what the hell is he talking about?" Ko joked on Wednesday.

"But it makes me get over quickly what just happened," she said.

"So in a way, bad jokes are kind of my criteria."

Ko's search for the right caddie has been an intriguing storyline for the media throughout her short span on the LPGA Tour, but it appears Victorian bag man Hamilton, for the foreseeable future at least, has landed the top gig.

The New Zealander auditioned eight caddies throughout her rookie season, an understandable game plan given she had not seen many of the courses on the largely US-based top flight tour and was still trying to figure out what type of traits she wanted in an on-course helper.

The dynamic between Ko and Hamilton seemed natural and relaxed this week as the pair tuned up for Wednesday's pro-am at Royal Melbourne ahead of Thursday's start to the LPGA-sanctioned Australian Open.

Hamilton was within ear shot of his player when this reporter relayed Ko's playful comments about his "bad jokes".

With a smile and turning one eye to Ko, Hamilton responded: "That's just because she's a Kiwi, she doesn't understand good humour.

"All my good jokes are wasted on her, I think," he said.

Then, more seriously, Hamilton continued: "That's kind of part of my job, to keep her relaxed. If they're getting pissed off or whatever, it's part of my job to try and make them laugh and remind them that it's just a game and that mistakes are going to happen.

"It's more important how you deal with those mistakes," he said.

It is a relationship that began officially two months ago, but had its origins in the US where the pair live in close proximity to each other in Orlando.

Through a friendship with Ko's manager, Hamilton and the barrier-breaking teenager developed a connection and for the Australian, it was an offer "too good to pass up".

And his credentials weren't exactly a hard sell to Ko, either.

Hamilton once caddied for another record-breaker, former world No.1 Yani Tseng, who was the youngest player ever to win five major championships.

It puts Hamilton as well placed as anyone to help Ko - predicted to be the sport's next transcendent star – deal with the pressures of having the world at her feet.

It is a role he understands and takes seriously, even though he downplays his influence.

"My job is pretty easy," he said.

"When you just have to tell someone to hit it to a certain spot and they do it every time, like she does, it's not that hard."

Should the Ko-Hamilton partnership remain a long-term deal, the Australian is in for a hell of a ride.

Even if Ko retires at 30, which she says she will, there are still a lot of major titles and a lot of money available in that time for a player with her freakish gifts and will to win.

A lot happens in Ko's life in just one year, let alone the 13 she has left before she turns 30.

At last year's Australian Open, she left the impression of a girl who would one day soon be the full package, but wasn't quite yet.

This year, as soon as she walked into the media room, she looked like a superstar.

She had a different appearance and sound.

The trademark glasses were gone, and she spoke with a noticeably American accent, more confident and polished.

In her first year on the LPGA Tour, she won three times and had 12 other top-10 finishes. Her success at such a young age is unprecedented.

And, as Ko said on Wednesday, "this is only the start".