Victorian James Marchesani proved that aggressive play wins out after capturing his maiden professional victory in brilliant fashion at the WA Open.

The 35-year-old kept his scorecard clean with an equal-course record seven-under-par 65 on a windy Sunday at Secret Harbour to finish 17-under-par.

Marchesani (68-69-69-65) entered the final round in a three-way tie for the lead alongside reigning champion Oliver Bekker and Jasper Stubbs, with the trio remaining neck and neck the entire final round.

South African Bekker looked the betting favourite to go back-to-back as he held a commanding two-shot lead when the group stepped on to the 14th tee box.

Conservative play was the theme on a windy final day at Secret Harbour in the venue’s first crack of hosting the WA Open, but the dull golf took a back seat down the closing holes providing an exciting finish for a healthy crowd of locals.

Bekker remained vigilant hitting iron off the tee but a hiccup from the leader came in an untimely bogey on the 14th, coupled with Marchesani’s third birdie for the day to open the door for the Aussie.

Aggressive play all day nearly became Marchesani’s undoing on the 15th, opting for driver into the par-4 found him playing from the fairway bunker then into the greenside trap.

But an incredible shot out of the bunker followed by a clutch par-saving putt proved the difference as he won the tournament by one shot.

The forgotten man Stubbs reminded the crowd of his presence with a brilliant second on the par-5 16th that was stuck to six feet, rolling in an eagle putt to steal a share of the lead.

With one hand on the trophy, Marchesani ripped it from the grasp of his competitors with the shot of a lifetime at the feature 17th par-3, landing it on the perfect spot on the green which funnelled his ball down to the hole for a kick-in birdie.

Carding 11 career top-5s without a win, the Australian could not believe his own performance after capturing a maiden Challenger PGA Tour of Australasia victory.

“If you told me I shot a 65 to win today . . . I would of told you that you were crazy,” he said after the win.

“It’s hard to wait and think when, guys are so good out here you just can’t miss a shot.

“I stuck to my guns, stuck to my plan.”

Reeling from the win, Marchesani said Sunday’s performance was up there for lifetime rounds.

“I’m sure I probably have (played better), but not under the same circumstance. So yeah, it was obviously the one I’ve been searching for on a Sunday,” he told Golf Australia.

With local pro Brady Watt on the bag for the last day, Marchesani said they felt confident in their plan on the 17th tee before he hit the self-described “shot of the week”.

“Thought I had a good number . . . I knew that the slope would help me and push it in there,” he said.

“I didn’t think it was as close as what it is, it’s the sort of shot that wins you the trophy.”

Eagles on the third and 16th gave 24-year-old Stubbs (66) a solo-second finish to follow up his tied third at last week’s WA PGA Championship in Kalgoorlie.

Consecutive bogeys dropped Bekker (67) down to third, a heartbreaking finish from the defending champion who relocated to Perth last year after winning the WA Open at Mt Lawley.

Earlier in the competition 18-year-old local Spencer Harrison, recipient of this year’s Cameron Smith Scholarship, had the shot of the week when he aced the seventh with a clean 8-iron from 157m out.