The affable Thai sank an eight-foot birdie putt to beat Australian James Nitties 2&1 in the final at Lake Karrinyup.
Aphibarnrat was the final player to qualify for the match play phase – the top 24 players after 54 holes of stroke play proceeding to six-hole match play.
“I’m last guy in top 24. I think I’m last guy to arrive this week as well,” a smiling Aphibarnrat said at the victory presentation after securing his fourth European Tour victory.
He did not arrive in Perth until tournament eve, after only entering the tournament last Sunday.
“I love to play,” he said. “I try to win every week. I know it’s not possible but I try my best. I don’t think I’m going to sleep (tonight). A lot to celebrate and Thai food of course.”
Aphibarnrat, 28, is showing a liking for match play. His most recent European Tour win also came in the head-to-head format, at the Paul Lawrie Match Play in Scotland in 2015.
On Sunday, he took five extra holes to beat Japan’s Yusaku Miyazato in the second round, and also dodged a bullet to edge Australian Lucas Herbert at the first extra hole of their semi-final.
Texas-based Nitties found tree trouble in the final with a series of wayward drives, before Aphibarnrat struck the killer blow by driving the green at the fourth hole and sinking a five-foot eagle putt.
He delivering the coup de grace at the next hole.