Ackerman, ranked 1,321 in the world, clung on to the lead he held after day three to win by two shots with a closing 68.

His four-under-par Friday in tricky winds on the Gunnamatta course at The National left him at 15-under-par overall, just ahead of Australians Blake Windred, Nathan Barbieri and amateur Harrison Crowe at 13-under.

Ackerman, 25, from San Francisco, has been playing the last couple of years on the ISPS HANDA PGA Tour of Australasia without conspicuous success. Previously his only top-10 finish was in last year’s Isuzu Queensland Open last year.

But this week he birdied five of his first 10 holes in round one to start out hot, and he was at or near the lead throughout the week, negotiating Thursday’s drama when high winds forced an abandonment.

Blake Windred now sits in second on the Order of Merit and close to a DP World Tour card. PHOTO: Stuart Franklin/Getty Images.

“It hasn’t hit me yet, because I didn’t know where I stood until I was coming to the last hole,” he said. “I told my caddie not to let me know. We had a bet that if I didn’t birdie one of the last two, I’d buy him a case. I didn’t so I do.”

Ackerman was three ahead when he pitched it to a metre and made birdie at the short par-4 12th, and he was mostly steady all the way in other than a three-putt bogey at the par-3 16th where the margin was trimmed to two. He made commercial pars at the short 17th and the par-4 18th, tapping in at the last to seal his first victory and a $36,000 winner’s cheque.

The Californian also picks up two years’ exemption on the Tour, meaning that he is likely to skip the remaining three events on this season’s Tour and head home to see his family in America.

It was his past coach Alex Murray who first suggested some years ago that Ackerman head overseas to play golf.

“It hasn’t hit me yet, because I didn’t know where I stood until I was coming to the last hole. I told my caddie not to let me know. We had a bet that if I didn’t birdie one of the last two, I’d buy him a case. I didn’t so I do.” - Derek Ackerman.

“He wanted me to play internationally, playing different conditions, different courses. I had some connections out here to make it feel like home. I came here for a family trip three years ago, got to play Royal Melbourne, played New South Wales with my Dad.

“I love links golf, especially courses like this, because you have so many shots that you can hit. It’s not just a stock shot like some American golf courses. I was trying to do the Brooks Koepka path in a sense. It’s part of the path for me.”

The result was significant also for Blake Windred (67 today), who leapt Andrew Dodt and moved into second place on the Australasian Tour Order of Merit, a race that offers three DP World Tour playing cards in a couple of months’ time.

Jed Morgan, who finished T12th, is unassailable on top after his win at the Fortinet Australian PGA Championship in Brisbane.

The other big winner was Sydney amateur Harrison Crowe, winner of the Golf Challenge NSW Open, who backed it up with a T3 finish to emphasise his potential.

The battle for the three European cards resumes at the CKB WA PGA Championship at Kalgoorlie Golf Club from 21 April, with three events remaining on the schedule.