Firing a first round 7-under 65, Marchesani looked in fine form from the get go, racing out of the gate with three birdies on the first three holes.
A bogey on four stunted his momentum but he was able to quickly re-gather composure with three more birdies to close the front-9.
“It was a nice start, especially out here it’s always nice to get a few birdies early,” Marchesani said following his opening round.
“It gets your confidence going on the greens and you’re able to try and wiggle a few in.”
On to the back-9, the 26-year-old pocketed another three birdies before the 16th, and then on the 17th he was struck with horrible luck but was able to take in his stride.
“I hit it pretty solid on 17 in to the left rough and I was kind of blocked out. The second shot I hit about pin high then it bounced about 30 metres long up near a fence. On the green, I had a four and a half footer that hit the back of the hole and came out,” Marchesani laughed, who walked away with a double bogey.
Marchesani clawed back a little more ground with his 10th birdie coming on the par-3 18th and will head in to round two on a good note.
“I’m in a pretty good spot. There’s obviously still the afternoon group to go but as long as I keep staying patient on the greens and keep hitting the ball the way I am I should hopefully be around on the weekend.”
Queenslander Brett Rankin was the big mover in the afternoon field shooting 5-under 67 to be in outright second position.
“I played really well today. I hit 14 or 15 greens which you’ve got to do around here because it’s hard to make putts,” Rankin said.
“I drove the ball really well and hit it really nicely and just didn’t miss any short ones which again is pretty crucial around this course.”
Despite the one bogey in his round, Rankin is happy with his position after the first 18 and will look to capitalise on his strong start.
“I bogeyed 11; I hit a decent chip just got an awkward bounce then had bout an eight footer and missed that,” added Rankin.
"It was nice to bounce back and hit a couple of birdies coming home for a really solid round.
“If I can keep hitting the ball where I am I can give myself enough opportunities, I had a whole bunch of eight and 10 foot putts as well which didn’t go in but they could have.
“There’s not too many guys who shoot 7-under everyday so I’m in a good spot.”
Daniel Nisbet (QLD), Peter Martin (QLD) and Adam Stephen (NSW) are tied third on 4-under 68.
Defending Champion Brad Moules (SA) has a share of 6th alongside Damien Jordan (QLD) and Matthew Stieger (NSW).
PNG local amateur Soti Dinki finished the round inside the top-10 on a score of 2-under 70 along with Simon Houston (WA), Andrew Schoenwillie (VIC), Alex Pitty (NSW) and Fraser Wilkin (NZ).
The SP Brewery Papua New Guinea Golf Open will be played from 4-7 May at Royal Port Moresby Golf Club in Royal Port Moresby, Papua New Guinea with the field vying for a prize purse of AU$142,000.
The winner will receive Official World Golf Ranking Points and become fully exempt on to the ISPS HANDA PGA Tour of Australasia for the remainder of this season plus a further season.