Cameron Smith thought a third Australian PGA Championship would be beyond him after posting a final round of 68 to seal victory at the Royal Queensland Golf Club.

The home favourite, a two-time winner before in 2017 and 2018, finished 14 under par, with a three-shot lead over fellow Australian Jason Scrivener and Japan's Ryo Hisatsune.

Amid a closing day interrupted by lightning strikes across the course, Smith recovered from a slow start to post three birdies over the final seven holes and claim the trophy.

Though seldom off the pace across the weekend, the defending Open Championship winner says he was not sure if he would be in the conversation for victory before he teed off.

"I really didn't think I had it in me at the start of the week," he stated. "I was a bit scratchy [but] the game has got better and better as the week went on, other than the front nine today."

On the weather, he added: "You are in the mojo a little and for it to be stopped not once but twice was a little frustrating. But I just held on and played really solid those last eight holes."

Hisatsune was best in show on the final day with an impressive 65, a feat matched only by Australian Geoff Ogilvy and Englishman John Parry.

The latter's performance was enough to seal a joint-fourth-place finish overall, tied with Min Woo Lee on nine under par.