Ten strokes off the lead after three-over 73 on day one and five back when he teed off on Sunday, Buchanan played his final 48 holes in 17-under par for a 14-under total.

After a wait of more than an hour, it would prove to be more than enough, finishing three clear of Victorian Phoenix Campbell (64), Hunter Valley’s Corey Lamb (68) and West Australian Kathryn Norris (69), who chipped in for birdie on the final hole to cap the best week of her young career.

Norris and overnight leader Brett Rankin (73) both made steady starts playing in the final group before faltering around the turn.

Norris made bogey at both nine and 10 as Rankin made double-bogey at 10 and bogey on 11.

Fast out of the blocks with consecutive birdies at one and two and an eagle from 15 feet at the par-5 4th, Buchanan soon gained the ascendancy.

Playing six groups ahead of the final group, the 22-year-old kept the foot to the floor.

Despite a dropped shot at eight, he made the turn in five-under and then added another birdie on 10.

He assumed the outright lead with a birdie on 13 to get to 13-under, only to fall back to 12-under with a three-putt bogey at the par-3 14th.

It would be just a slight stumble as Buchanan responded with birdies at 15 and 16 to reach 14-under, making two superb par saves on both 17 and 18 to set a mark that would remain unmatched.

It is Buchanan’s second win in three weeks on the Challenger PGA Tour of Australasia, his win a fortnight ago at Kalgoorlie proving crucial down the stretch at Willunga.

“I think it made a huge difference,” Buchanan said of the confidence he gained from his win at Kalgoorlie.

“I said to my caddie, Patty, on 16 after I hit that iron shot, I said, ‘Kal’s made a big difference to me.’

“Just a little bit of self-belief and knowing that you can actually do it when you need to.”

Conceding that he was not in the best frame of mind when he bogeyed four of his final six holes on Thursday to be 10-strokes off the lead going into Round 2, Buchanan knew he needed a good start to the final round to be any hope.

“Five shots back, I didn’t really know,” added Buchanan, who now moves into top spot on the Challenger PGA Tour of Australasia Order of Merit.

“I said to my caddie, if we start off hot, you never know. That’s kind of what I did and just ran with it.

“I wasn’t overly happy (after Round 1) to be fair. Just a couple of three-putts. I feel like I lost my concentration a bit but hit it flawless since then.

“Just strived to play as good as I could every day.”

Two weeks after his historic G4D Tour win in Spain, Steve Alderson made it consecutive Webex All Abilities Players Series South Australia victories at Willunga, finishing three strokes clear of Wayne Perske with Tom Ryan one shot further back in third.

“I had a lot of local people wanting me to do well and just back up what I did in Spain,” said Alderson.

“I just didn’t want to crash and burn and just be like a one-hit wonder basically.

“It was quite tough coming down the stretch for me. My brain was in overload. I found it hard to hold back the tears on the last couple of holes, but had a big enough lead which helped to just to get the job done.”

In the Webex Junior Players Series South Australia event, Kooyonga Golf Club’s Malachy Marshall added to his SA Boys’ Order of Merit win with a seven-stroke victory over Billy White.